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Some Common Questions

Here are some common questions about diesels.

The valve problem you describe can be caused by:

1] excessive idling [longer than 5 minutes]
2] wrong type, grade, or weight of lube oil
3] not bringing the engine up to operating temp before shutdown
4] operating at the incorrect engine load or speed ["babying" the engine ]
5] old fuel, or fuel with low cetane
6] restricted exhaust system

Also, those cast iron Yanmar exhaust elbows are problematical. They like to accumulate carbon, and clog. I have "fixed" several engines that refused to run by replacing just the elbow ! This part should be replaced with a non clogging type elbow. Beta Marine's exhaust elbows are made of stainless steel, and will not clog.

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To clean oil from the engine space:

Use TSP and a nylon scrub brush, then flush with water. After drying, use "Brakleen" available at auto parts stores. Now scratch the surface with 100 or 80 grit, wipe with alcohol, and use bilge paint. I like the white paint, it is also available in grey.

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Here's the short version of restarting an old diesel engine.

1] drain oil, remove oil filter and secondary [ on engine ] fuel filter

2] get the correct oil filter [check the manual for the correct part number, don't assume the removed oil filter is correct] and secondary fuel filter. NAPA auto parts has top quality filters, and can cross reference many OEM part numbers.

3] check trans oil for correct type and level

4] using Shell Rotella 15W40 oil, squirt some oil [about 1/2 pint ] into the engine block where the oil filter is installed. This will prime the oil pump. Oil must be introduced into the passages around the threaded nipple, [ this leads back to the oil pump ] NOT into the nipple. NOTE - All diesel engines require diesel grade oil. NEVER install gasoline grade oil into a diesel engine !

5] Install new oil, new oil filter, new fuel filter. NOTE - ALWAYS install the fuel filter dry. If you pre fill the filter, you have just bypassed it, and have introduced contaminants. BIG no no.

6] remove the fuel hose from the fuel supply pump, install clear vinyl tubing, lead tubing into a CLEAN, fresh can of diesel fuel.

7] bleed the fuel system, as detailed in the owner's manual. This will ensure the expensive fuel injection pump will have lubricant during engine cranking.

8] remove all glow plugs, spray "fogging oil" [ available at NAPA ] into the holes. This will prelube the cylinders and piston rings. NOTE - Many engines do not have glow plugs, such as Yanmar, Volvo, or some Perkins engines. The idea is to get fogging oil into each cylinder before cranking the engine. Removing the air horns or intake manifold may allow access to the intake valves, where oil can be sprayed. Removing the fuel injectors will also allow direct access to the cylinders, HOWEVER, one must work surgically clean with fuel injection systems. Skip F.I. removal unless you are experienced. Some engines, such as early Universal and Yanmar diesels, have a compression release lever. This slightly opens the exhaust valves to relieve compression while cranking. Spraying fogging oil on top of the exhaust valve head will allow cylinder pre lubrication.

9] close c-cock and remove raw water impeller

10] remove the valve cover and lubricate all pushrod ends, rocker arms, and valve stems with lube oil. Reinstall the valve cover.

11] shift into neutral, put fuel control at low idle speed, and crank the engine for 30 seconds. rest for 1 minute, and crank again for 30 seconds while observing the oil pressure gauge. This will result in oil pressure throughout the engine, with the cylinders, piston rings, intake and exhaust valves being lubricated with fogging oil. NOTE - the engine will rotate very fast, as there is no compression with the glow plugs removed. There will also be a spout of vaporized oil from each glow plug hole, the mess can be minimized by placing a thick rag along the top of the engine.

12] check the fresh water coolant for correct level

13] Reinstall all glow plugs. Place the fuel control to full engine speed. Be sure the engine shut down devise [ usually a pull cable ] is disengaged.

14] follow the engine manual start procedure, and start the engine. Immediately slow the engine to 1/2 speed once it starts. Run the engine no longer than 2 minutes, or you risk burning the rubber exhaust hose.

15] Install the raw water impeller, check trans oil, engine lube oil, and coolant levels.

16 ] if the boat is ashore, lead a hose from a bucket to the raw water pump, and fill he bucket with water using a garden hose. Start the engine, and run it at 1/2 speed for 15 minutes, being sure to keep the bucket full. DO NOT idle the engine, as this will accelerate engine wear ! Check for leaks while running.

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New Engine Operating Procedures
I have conflicting advise about the correct way to break in and operate my diesel - any suggestions? Harry

[JED] Usual break in procedure - vary the rpm from about 3/4 engine speed to normal criuse rpm. That means you shouldn't run at any certain rpm for longer than about 1 hour. Vary the rpm so the engine doesn't develop a fixed wear pattern - and be certain you are using the correct lube oil. Don't run at max rpm for more than a few minutes, until the engine is broken in.

General engine operating rules - start engine, run in neutral at a speed just above low idle for no longer than 5 minutes. [I'm assuming the ambient temp is akin to spring or summer.] Engage trans into gear, and get underway, while warming up the engine under light load [ don't run over 1/2 max rpm ] When temp gauge approaches operating temp, run at normal cruise rpm, usually about 3/4 of max rpm. The object is to bring the engine up to temp as soon as possible, so as to avoid the increased wear associated with a cool engine.

AVOID EXCESSIVE IDLING! That's running it at low idle with no load for more than 5 minutes. This accelerates the engine wear considerably!

When shutting down, run at reduced rpm [just above low idle] for 5 min, then shut down. Some engine makers suggest to give a final spurt of fuel [rpm] and then shut down, to clear carbon from the cylinders. Check the manual.

If the engine is making lots of exhaust smoke after getting to operating temp, find the reason why and correct it! There should be barely visible smoke under normal operating conditions.

BE SURE that when the engine has been running under load for 30 min, that it is running at the correct operating temp. If it's running too cool, you are, in effect, operating it at all times while in idling mode. This will soon be expensive! For Fresh water cooled engines, that's about 180 degrees F. Raw water cooled engines must run at a lower temp that won't allow the salts to precipitate out of the salt water. They operate at 140 F. This is another reason raw water engines don't last as long as fresh water cooled engines.

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Underpowered Boat
I am considering the purchase of a 30 foot sailboat with a 13 HP diesel. Several reports indicate this power plant is underpowered for this size boat. Any comments, solutions (if a significant problem)? Thanks, Andy

[JED] If your vessel is indeed underpowered, the addition of a more efficient propellor for your engine / hull configuration will assure all the engine's power is used in driving the vessel. Let's assume the engine is in good mechanical condition, and is capable of running at it's rated power output. (Don't jump this hurdle yet, many diesels don't make their rated power due to restricted fuel systems, old fuel, restricted air or exhaust systems, maladjusted control cables or governors, leaky valves, improper injection timing, etc.)

Here is a rule of thumb for displacement hulls.

If a fixed propellor, ensure the engine is reaching max rpm while the boat reaches hull speed. This will allow the engine to attain it's maximum power, and drive the boat efficiently. There should be no black smoke at hull speed, as this indicates the engine is overloaded. Assuming the boat's bottom is clean, and the engine is getting sufficient air, [clean air filter, etc.] black smoke at hull speed means the propellor is too steeply pitched. (There are a few more reasons for black smoke, but we are talking propellors.)

Folding props of the racing type [Martec brand] are great under sail, but are not designed for efficientcy under power. This is fine with commited racers.

Folding props such as Max Prop would be advantageous for most any sailboat, due to manual blade pitch adjustability, and excellent astern powering ability. They also make minimal resistance when sailing. They are expensive, however. This is the route I would take, were I in your situation.

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Engine Alignment
Can you suggest a methodology for engine - shaft alignment? We put the boat in the water last Friday and the alignment is significantly out. Thanks - Bob

[JED] Engine alignment - short course:
  1. Ensure the engine mounts can be adjusted, [no heavy rust on threads] and are not fatigued, sagging, or oil soaked. If the mounts are over 10 years old, they are suspect. Ensure they are firmly attached to the stringers. The stud should be vertical, not canted to one side. This puts a side load on that mount and accelerates wear, it also makes alignment difficult.
  2. Disconnect the couplers by bolt removal and separate them - note any rough misalignment.
  3. Clean the mating surfaces of the couplers of any rust.
  4. Adjust the engine/transmission mounts to get the couplers in the same plane, by eye. This is the rough alignment. You may discover the mounts run out of adjustment before the engine is aligned. In this case, I would suggest it be evaluated by a mechanic, as the engine mount/strut system will have to be rebuilt.
  5. Now slide the shaft coupler forward to contact the transmission coupler. They should mate evenly - just imagine both couplers are pistons in the same cylinder - contact should be made flat and square - check with a straightedge around the couplers for a concentric fit.
  6. Now for the final adjustment - get comfy, and insert a .004" feeler gauge between the couplers. Check for even fit all around the coupler circumference. Adjust the engine mounts to this standard, while maintaining the couplers inside the imaginary cylinder. Take your time, it's not easy!
  7. When done, torque down the engine mount lock nuts and recheck alignment. Now re-install the coupler bolts using new lock washers - NOTE - these bolts are fine thread, for strength and vibration resistance. A jumper wire between opposite coupler bolts - 10 gauge - can be used to bond the prop shaft.
  8. Consider installing a "Drivesaver" or other flexible unit between the couplers to compensate for the minor misalignment that happens underway.
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Running Problems
My diesel engine suddenly stopped running on our way back from a weekend cruise. After the engine died I was able to re -start the engine in neutral. It would run for 30-45 seconds, at low rpm. Then rev up for a few seconds. Then produce a little white smoke out the exhaust. Then die.

Any suggestions on the cause of the problem? Lynn

[JED] Whenever a diesel stops running, it's 98% certain it's due to a fuel supply problem. Strongest suggestion - Get the Shop manual and read it. It's an excellent investment.

I would check the primary fuel filter/water separator [Racor filter] first for water in the bottom of the fuel bowl. (This is the clear section of the Racor filter.) It is hard to explain the appearance of water in the bowl, though it can be checked this way - open the drain on the bottom of the fuel bowl and catch a small sample [shot glass amount] in a glass jar. Put a similar amount of water in an identical jar and compare the two. Hold the jar over your head and look up into it - water is heavier than diesel fuel, and will sink. If water is confirmed, drain the entire contents of the fuel bowl into a container for disposal.

Also, the fuel in the bowl should look like Budwieser, not like maple syrup. Syrup color indicates the filter needs changing. (You may be in a state that dyes the fuel red or green for tax reasons, ignore these colors.)

Any black kinda gooey stuff left in the Racor bowl or in the drain container? This is proof of a microbe infestation that will clog your filters. More on this below.

Check the Racor for the model #, and get 2 replacement filters. (I prefer the 10 micron filters, a micron is one millionth of a meter.) Also get 2 replacement secondary filters [from the engine dealer] at this time. Following the directions, install the new filters. (One set is to be kept aboard.)

Be sure to first clean out the Racor bowl with "Brakleen", available at an auto supply store, if black junk is found. Spray it into the top of the open Racor filter body, and let it drain out the bottom. All the black junk must be removed. Check the appearance of the old Racor filter you removed to a new one - if it is black, that's microbes.

Buy some 'Biobor" [biocide] and diesel fuel stabilizer, and add the correct amount according to your fuel tank capacity. Now get some fresh fuel and fill the tank to dilute the cruddy fuel already in the tank.

Now open the shop manual and learn to bleed the fuel system.

Start the engine, and maintain a watch on the Racor filter - that's why there is a clear fuel bowl! You are watching for water and dirt to accumulate, which means the Racor is working correctly. However, too much water, dirt or microbes can overwhelm any filter so drain off the water and keep that filter renewed. A vacuum gauge [Racor part] installed on the filter body will tell you when the filter needs changing - an excellent investment.

Remember, you have added a biocide that killed the microbes, but their bodies remain. The Racor will remove them as the engine runs, so in time, the filter will last longer between required changes.

If you have a heavy microbe infestation, consider having the fuel in your tank "polished", which means you hire someone to filter the fuel that's already in your tank. Check with your marina for this service.

I would also check to ensure that the fuel tank vent hose is unobstructed - any restriction here and a vacumm is created in the tank.

Consider getting and religiously using a prefilter/funnel that will stop water and crud from being introduced into the fuel tank. This is your FIRST LINE of DEFENCE against fuel contamination.
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Black Smoke and Exhaust Problems
I am hauling our boat soon and I was wondering about our prop and if it is the correct size for the engine. I say this since the engine will start to blow black smoke once it reaches 2900-3000 RPM. Dave

[JED] This must be corrected, as you are limiting the useful working life of the engine. Possible reasons for black smoke -
  • prop pitch is excessive [engine is overloaded and is running too rich]
  • dirty bottom or prop
  • transmission problem
  • old fuel [very common]
  • kerosene being burned instead of diesel fuel
  • air inlet restriction
  • turbo problem [only for turbo charged engines]
  • engine cannot get enough air while running at high rpm [engine space not properly ventilated]
  • restricted intake or exhaust valves
  • improperly adjusted valves
  • restricted exhaust system
  • injection timing incorrect
  • injector problem
  • low engine compression
  • engine is not reaching correct operating temperature
I would check the simple things first, as in the list above. Did your boat always have this problem, or did it develop suddenly, or gradually?

If your fuel supply [in the boat] is more than 6 months old, and no fuel stabilizer has been added since you filled the tank, it is suspect. Most sailboat fuel tanks contain at least SOME very old [several years] fuel. The tank should be pumped dry, inspected for condition, and fresh fuel [with stabilizer] added. Also change all fuel filters.

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Volvo Longevity and Checklist
In my boat sits a very well running 1979 Volvo MD11C diesel. No problems at all, starts right up (although takes about 20 seconds if its cold out), runs great, burns less than half a gallon an hour, is a little smokey, but I hear all older diesels were.

I am starting to get paranoid about this engine. It has given me no cause, but still, I am. What if it just stops working?

Should I replace something before it fails? What about the raw water cooling elbow? It looks like the original one, and I was told these things don't last more than 10 years. Mike

[JED] No reason to get paranoid, just remember that these older engines, particularily raw water cooled ones, have limited service life remaining. This is one reason why an older boat is cheaper to buy than a new boat.

Bottom line on this Volvo - should it fail and require major work, such as rebuilding, it will be more cost effective to replace it with a new diesel, such as a Beta Marine. Volvo parts prices are very high [a new exhaust manifold costs $550] and parts availability on any old Volvo is a problem. What usually happens with these raw water cooled engines is that the head casting finally rots from the inside out, resulting in raw water in the lube oil. The result is a major engine failure. Ditto for the exhaust elbow. The elbow [on any water cooled marine diesel engine] will rot internally, possibly allowing exhaust water to be misdirected backwards into the engine, resulting in water in the cylinders. This will also cause a major failure.

Should any of these two events occur, it's just not cost effective to rebuild an older Volvo. A new Beta Marine diesel engine will provide you with the latest diesel engine technology, no parts availability problems, and a 2 year warranty.

I suggest that a qualified marine diesel mechanic evaluate this engine, for general condition and operation.

A few things to check -
  • engine mounts [old mounts sag, can bend the prop shaft]
  • stuffing box [usually difficult to reach, so it gets ignored]
  • Walter V drive
  • general engine running qualities
  • type and amount of exhaust smoke
  • fuel quality
  • raw water pump, strainer and hoses
  • intake air silencers [oil accumulation is a fire hazard]
  • valve adjustment
  • no load [max] rpm
  • low idle rpm
  • exhaust hoses
  • etc., etc.
A compression test will reveal much about the internal engine condition, and will provide clues to it's remaining service life.

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OEM Lube Oil Filters
Is looking for the "correct" oil filter really necessary? My observation is that the center hole and gasket setup is pretty much universal for spin-on type filters. It seems that you could do just as well if you were to find a quality filter (Mobil 1 with synthetic filter media comes to mind) that will fit in the available space. Is there anything special about filters for diesels? If so, would a high end automotive filter for a diesel engine be a good alternative to hunting down a OEM filter? Thanks, Ed

[JED] The OEM [original equipment manufacturer] filter is the type I recommend. Yes, they do cost more than the filters at K-Mart, but the correct filter will fit without leaking, and meets all the engine maker's specs. Why scrimp on this inexpensive filter when the integrity of the entire engine is at stake?

All spin-on lube oil filters have a bypass valve built into them, so the oil flow can be diverted past the element, should the element become clogged. This valve also opens whenever the oil pressure reaches a certain value, as when starting a cold engine, and the oil is very thick. (Particularily true if using non-multi-weight lube oil, such as 30 weight.)

If the valve is located ot the bottom of the filter, and the filter installs on the engine in an upright attitude, "filter flushing" will occur at engine startup. That is, all the accumulated dirt and crap that's trapped by the filter and laying in the bottom of the filter, will be flushed into the engine's oil system when the bypass valve opens. This situation is avoided by installing a filter with the bypass valve that's located in the top of the filter.

How does one know where the bypass valve is located in the non OEM filter you installed on your engine?

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Props, Pitch and Gearing
What are the advantages to the 4 blades over 3 blades and/or change of prop pitch for that matter? Baffled Bob

[JED] A muli-blade prop will deliver more thrust than a 2 blade. Great for fighting currents or towing.

Look at any go-fast boat's prop, [Scarab, Cigarette, etc.] you will find them to have extreme pitch, [or advance] and be of small diameter. This is a high rpm prop [turns at a high rate of speed] to force water past them in a concentrated, high speed cylinder of water. You can think of this prop as being the equivalent of 5th gear in your car, as it's an ideal design to obtain top speed for this planing, lightweight type hull.

Now look at a tugboat or trawler yacht. The props are of large diameter, with minimal pitch. This design can be thought of as 1st gear in your car. That is, ideal for moving heavy loads, such as when pushing a displacement hull, or for towing.

Remember, any displacement hull must push aside water that is equal to the boat's displacement for every waterline length it travels through the water. That is very demanding work, and requires a prop diameter and pitch that will allow the engine to attain it's rated RPM, so it can develop it's rated horsepower. If this "gear ratio" is correct, the boat will not appreciably slow down when encountering waves or wind.

For example, if a sailboat has a prop installed that has too much pitch, it is, in effect, geared too high. It will slow down when fighting waves or wind. It's like driving around town in 5th gear in your car, when second gear is what's required to move the load while maintaining the correct engine rpm. If your car is going 20 mph in 5th gear, and you attempt to drive up a hill, the engine cannot maintain that speed, due to the increased load and incorrect gearing. The hill can be crested by downshifting to 2nd gear, so as to allow the engine to operate at a higher rpm, and develop it's rated horsepower.

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Hard Starting Engines and Starting Fluid
My diesel engine is difficult to start, unless I use starting fluid [ether]. Somebody told me not to use this stuff - why not? It works great! Ken

[JED] Ether is very volatile and has a low flash point. Ether, in contrast to diesel fuel, will not burn progressively, but will detonate inside the cylinder at a lower temperature than diesel fuel. This quality makes it ideal for starting cold diesel engines. It is factory installed on many brands of heavy truck engines [Caterpillar, Cummins, Detroit Diesel, etc.] so the operator can introduce ether into the engine while sitting in the driver's seat. However, be aware that ether is being used, in this application, on large [12 liters or so] diesel engines that are VERY robustly built. I would NEVER use ether in a small diesel engine, unless the builder suggested it. (Most builders say the opposite.) The risk of permanent, expensive internal engine damage, due to ether's explosion inside the cylinder, is too great. There is a very real risk of cracking the piston, piston ring, blowing out the head gasket, or even bending the connecting rod when using ether. If your engine will not start by using the factory start procedure, find the problem and fix it.

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Overheating and Cooling System Inspection
Please explain how I can determine the cause of my 20+ year old diesel engine overheating - Fred

[JED] Overheating problems are common on older boats, unless the engine has been correctly maintained through the years. Since you are having an overheating problem, may I suggest the following:

Evaluate the ENTIRE cooling system, from intake to discharge, in detail. Considering the engine's age, I believe this step to be imperative. Attempting to find the "one thing" that's causing the problem is frustrating and time consuming. This "Shotgun approach" to repairs is useless, as there may be several reasons for the problem.

Proceed this way:
  1. Start at the engine raw water intake thru-hull and external strainer. Inspect it for barnacles, hard growth, chicken bones, plastic bags, anything that would restrict water flow. The sea-cock should operate smoothly, and acually be fully open when the lever indicates so. DON'T assume this is the case!
  2. Remove the intake hose and check it. (This exact situation occured on a Passport 40 last summer.) As you proceed further, try to eliminate pipe elbows throughout the cooling system, as these are very restrictive.
  3. Remove the hose from the sea-cock and strainer, and bend it into a tight radius. If cracks appear in the hose [look closely] replace with new, WIRE WOUND, marine grade [NOT automotive grade!] coolant hose. A hose lacking internal wire reinforcement will collapse under water pump suction, particularily at high rpm. Now look through the hose for any hanging material or wavy walls that indicate old age. If the hose has been sitting in oily bilge water, it's probably been softened. New hose is the solution to these problems. Also use new stainless steel marine grade worm drive hose clamps, preferably with a smooth internal surface. The standard hose clamp with the perforated band allows the hose to be damaged while tightening it. DO NOT overtighten any hose clamps! If the hose is large enough to accept a "T bolt" type clamp, install one. These are far superior to worm drive clamps in critical applications, such as stern tube hose, wet exhaust hose, toilets, scuppers, etc.
  4. Now disassemble and inspect the raw water strainer for condition, remembering that if there is a leak here, air will enter the system. Check all gaskets and "O" rings. The strainer should be mounted no higher than the [at rest] waterline, or air may accumulate and air lock the system. Be very suspicious of plastic strainers, as they will crack from age, engine heat, vibration, etc. If no strainer is fitted, buy a bronze strainer to install.
  5. Now check the next hose as you did the first hose. We are now at the raw water pump. I would remove it for disassembly and inspection. If there is any sign of water leaking from the drive shaft, [usually green corrosion] it indicates the pump water seal is worn out, and the shaft probably needs replacement. If there are deep grooves on the inside of the pump body, a new pump is the only alternative. It is usually not cost effective to rebuild these pumps. Be aware, if the pump shaft seals are worn but not yet leaking water, it's possible that air can be sucked into the pump during operation. This will cause decreased water flow to the engine. Inspect the old impeller for missing arms, or parts. If the impeller is not intact, the missing parts are somewhere downstream of the pump. These parts MUST be found and removed! They usually lodge in the heat exchanger. Replace the impeller as a matter of routine. Check the pump cover plate for deep circular grooves, if found, turn the cover over and install, using a new gasket, and order a spare impeller, cover plate and screws.
  6. Check the pump pulley for rust in the V belt groove, and for security onto the shaft. The V belt should be replaced, and the old one kept as a spare. Be sure to tighten it to specs, and to retighten it after 5 operating hours.
  7. Check all hoses, downstream from the pump, as before. Any downstream hose need not be of the wire wound type, as these are never under suction, only pressure. Replace any rusty hose clamps, as stainless is susceptible to crevice corrosion. We have now ensured a consistant and reliable supply of raw water to the engine.
  8. Next, remove the thermostat and replace with new, using a new gasket. Be sure to get the correct temperature rated thermostat - usually 180 degrees F for fresh water cooled engines, 140 degrees F fror raw water cooled. DON'T just duplicate what you find, as who knows if the old thermostat is correct for your engine. Check the parts book, or order it from a dealer - and DON'T install an automotive thermostat!
  9. Check the pressure cap for condition - is it bent or very rusty? I would replace with new, and keep the old for a spare. BE SURE to replace with a cap that is correctly pressure rated for your engine! Check the manual.
  10. If the fresh water coolant is discolored, drain and replace with straight fresh water and radiator cleaner - get it from an auto store. After running the engine for several minutes at operating temp, drain the fresh water coolant. Follow the directions on the cleaner can. DO NOT put cold water into a hot engine - you may crack the block. Warm the water first. Now install a 50/50 mix of antifreeze and water into the cooling system.
  11. Try operating the engine under light load, to check for overheating. Be aware that many factory coolant temperature gauges are inaccurate. You will need either an infra-red heat gun [can be rented] or an automotive test themometer to accurately determine the engine coolant temp. Now run the engine at cruise rpm and load, while checking for an overheat condition.
  12. The fresh water system can also be pressure tested with a special tool, which can be rented. This will determine if there is a cooling system leak, [internal or external] and if the pressure cap is working correctly. Consider installing a coolant recovery system onto the engine - these work to keep the system filled and air free at all times.
At this point, any more work involves greater disassembly and testing. To proceed further:
  1. Depending upon your specific engine, removal of the heat exchanger may be straightforward or not. Beta Marine diesels are simple, as are Universal, early Perkins, Isuzu, Crusader [gas engines]. Yanmar and Volvo can get a bit more involved, depending on the specific model, you may need a knowledgable person at this point.
  2. Bring the heat exchanger to a radiator rebuilding shop, to have it cleaned and pressure tested. Tell the worker the correct operating pressure of the system, so he doesn't overpressurize it. In the mean time, change any zincs found on the engine.
  3. Install the rebuilt heat exchanger, using new O rings or gaskets. If a domestic water heating system is installed, bypass the heating tank temporarily. (They are notorious for air locking an engine cooling system.)
The above usually fixes engine overheating problems. To proceed further:
  • Remove the exhaust mixer. This is where the raw water and exhaust gases mix. If there is a raw water passage restriction, the engine cannot expell the required amount of heat. Symptom - lots of "steam" from the exhaust through-hull, and not much water expelled overboard.
  • Also check the following for restrictions - any hoses attached to the siphon break, the wet muffler, all hoses downstream from here.
  • Inspect for the presence of a stuck check valve located aft of the wet muffler. Sometimes, a check valve is installed INSIDE the wet muffler output. You will have to remove these large components from the boat to inspect them properly.
  • If the exhaust system, located aft of the exhaust manifold, is comprised of many pieces of cast iron pipe, junk it and install a real exhaust mixer. This cast iron pipe "Jungle Jim" type exhaust is very prone to leaks, cracks, and restrictions.
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Diesel Engine Maintenance and Repair Training
As an owner with little experience in engine diagnosis and repair, I'd love to find a way to become more knowledgeable in routine tasks like winterizing and summerizing the systems, as well as basic electrical diagnosis and repair. $50+ hourly rates for yard technicians provide a strong motivator! As one who learns better in a hands-on setting, a short course would work better than a book or correspondence/CD-ROM program, but whatever is available would certainly be helpful. Any suggestions? How did you learn to do this stuff? Charlie

[JED] This is a common question. Personally, I went to a marine diesel mechanic's school for my basic training, and worked in the industry for 20 years. Of course, this was my chosen career path.

For your situation, I suggest the first step is to obtain the operating manual, workshop manual and the parts manual for your particular engine. There is an incredible amount of info in these 3 books. Next, take an owner's course that covers the basics of engine operation and maintenance. Check with your engine distributor for these classes. There are also adult education classes that are generally applicable to diesel engines and electrical systems.

Should a boat owner request it, I am usually available for a hands on orientation aboard the owner's boat.

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Repowering with a Diesel
I don't want a diesel, as in my opinion, they smell, and spending close to $10,00 to put an engine in a $20,000 to $30,000 boat doesn't make any sense to me. Gary

[JED] Gary must be referring to the old diesel engine designs, when he says they smell. He's right, they smell like an old city bus.

In contrast, the latest generation of diesel engines burn VERY cleanly, with VERY minimal smoke and odor. The contrast between the old technology and the very latest in diesel engine design, as employed by Beta Marine, is amazing. The new low sulphur fuel certainly also helps to eliminate the smell. The new engines are also MUCH quieter, and run smoother [minimal vibration] than any old engine design.

Concerning engine replacement cost - the Beta Marine 10 HP 2 cylinder, fresh water cooled diesel engine, with transmission, can be had for about $4600. The 13.5 hp model sells for $550 more, and includes a flexible prop shaft coupling, oil change pump mounted on the engine, etc. Either one of these engines will push an 8000 lb. boat to hullspeed, when mated to the correctly sized prop. If the owner is willing to put some sweat equity into prepping the boat by removing the old engine, cleaning and painting the engine space, etc., lots of money can be saved. The mechanic now installs the engine in place, and the owner connects the engine support systems. The boat is launched, the mechanic returns for an engine alignment and general inspection, test runs the engine, and the sea trial is completed.

The mechanic validates the warranty, and that's it! This will be the routine for a new 10hp Beta Marine diesel to be installed in an O'day 27 this spring. The total budget for this upgrade is $6500.

Much of that $10,000 previously mentioned above, is spent upon neglected repairs that should have been done in the course of normal boat maintenance. Corroded stuffing boxes, hose clamps, rotting stern tube hoses, sagging exhaust hoses, collapsed water intake hoses, rusty shaft couplers, sloppy cutless bearings, and worn prop shafts head the list of "most neglected" items.

Last summer I installed a Beta Marine 13.5hp diesel into a C&C 35 for a customer. He had also installed a Martec folding prop, [for racing] which is not the most efficient device for forcing water past the boat. He was very happy with the performance, as the new engine, which replaced an old Volvo MD7A, drove the boat easily and quickly to hull speed. The new engine was so quiet, the owner decided NOT to add sound absorbing insulation to the engine space, as it was not needed! The new engine was also 1/2 the weight of the old Volvo.

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Buying an older boat
I am interested in buying a sailboat for coastal cruising. I see there are some 20 year old, 30' boats for sale in my price range and want to get opinions of this size boat for my expected use. However, I have no experience with diesel engines. Any suggestions appreciated. Kirk

[JED] If the engine is a Volvo, be prepared to either replace it, [most are raw water cooled, and are getting old] or pay OUTRAGEOUS parts prices, such as $338 for a 5 mm oversized piston, wrist pin, and piston rings. A Volvo MD7A [13 hp] will require 2 of these sets. Valve grind gasket set = $96; MD11 exhaust manifold [ only available from Volvo] = $550

Put this money into into a new engine, with a warranty instead. You will also get the significant advantage of an engine with the latest technology, that will result in easy starting, high reliability, smooth running, and very low emissions. Also, parts availability problems will be eliminated.

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Using a mechanic
If I decide to hire a diesel mechanic, what should I insist on getting for my money, and how much should I expect to pay? Nancy

[JED] A lot depends upon your area of the country and availability of suitable mechanics. In this area, [southern New England] most mechanics [or boatyards] charge $50/hour. Many charge $60 to $65 per hour, and I know of an exclusively Volvo business that charges $75/hour. Yep, there is NOTHING cheap about Volvos!

What you should get for your money depends on exactly what you want done. Before I hired anyone, I would first check his work references, and ask a few simple questions, such as - do you have any experience with this particular engine? Any intrinsic problems with this engine model? How long have you worked as a marine diesel mechanic? When can you start? What do you think of ABYC? If the answers are brief and vague, I would think hard before hiring anyone with a communication problem, or someone trying to bluff through the answers.

If you want a simple evaluation, I would expect the entire engine and related systems to be visually inspected, and then a written report, with repair recommendations, and optionally, price estimates for labor and parts. You may also want pictures of the problem areas. If there is any actual physical testing to be done, I would want the specific written results, ["engine compression good" is not good enough, I would want the actual figures] with repair recommendations, and again, optional price estimates for repair.

If there was a sea trial, I would want to be aboard.

Expect to pay a bit extra for pictures and a written report, as these take time and materials. Personally, I think it's money well spent, as it documents the boat's condition on a certain date.

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Buying a Pearson 323
I'm going to sea trial and survey a Pearson 323 has the diesel engine. Anything special with the hull survey I should look for? Kevin

[JED] I strongly suggest you get a diesel mechanic to check the engine installation. His findings can make or break the deal, financially speaking. These engines are getting old, most of the factory installed Volvo MD11s are raw water cooled, and parts are VERY expensive. [$550 for an exhaust manifold - you will need one if the engine was left with salt water in it over a cold winter.]

Engine acess is a HUGE problem with the V drive setup in this boat, and as a result, proper engine maintenance gets neglected. I would check the port side of the block for rust streaks, this indicates the exhaust manifold is leaking, probably for the above reason.

Consider a compression test on the engine - if it fails, the rest is academic, as I don't think you want to buy a boat that needs an engine rebuild, unless that fact is reflected in the price.

Other spots to check -
  1. All engine mounts. If there is heavy rust on the mount threads, engine alignment is impossible. If the mounts haven't been replaced in the last 8 years, they are suspect, as the rubber parts fatigue and sag with age. This also means the cutless bearing and shaft is now suspect.
  2. Stuffing box - it's buried under the engine, and gets neglected. If there is heavy green corrosion on it, it'll be difficult to get apart and repack. You may have to haul the boat, pull the shaft, and remove the stuff box and stern tube hose for repair or replacement. Again, a tough job for an owner to maintain, so the stuff box gets ignored.
  3. In the port side cockpit locker, there is an electrical junction box, located on the forward bulkhead of the locker. Expose it and check the wiring for corrosion. I'm betting it's a mess. Pearson put AC and DC panels next to each other. Add a little salt spray, and electrical gremlins appear.
  4. Check the fuel tank straps - I've seen several boats that have mild steel straps in contact with an aluminum tank, in a damp environment. Wanna guess what happens?
Personally, I would expect a large price reduction on any boat that had a raw water cooled, older Volvo. Not only are parts expensive and hard to find, the salt water that's been inside the block for years causes rapid rusting, leading to overheating problems when the water jackets get clogged. This process will be accelerated if the engine zincs were not properly maintained for the last 20 years. Ditto for a raw water cooled Atomic 4 gasoline engine.

The ONLY way to fix this is to disassemble the engine and physically clean out the passages. This will not be cheap - you may also discover, while doing this, that the head or block is rusted to imminent failure, or that the head bolts are rusted in place.

I've seen several Volvos of this type and age that will suddenly develop water in the lube oil, due to the engine head or block rusting through internally. When this happens, it's not financially feasible to repair the Volvo, so a new engine gets installed. This is fine, as long as the new engine cost is reflected in the boat's purchase price.

Beta Marine has an ideal engine replacement for this boat, with their fresh water cooled BD1005, a 28 horsepower diesel. Not only does this engine provide 4 more horsepower than the old Volvo, it has 3 cylinders compared to the Volvo's 2. This means the Beta Marine engine will run much smoother, with minimal vibration. Also, the available V drive Hurth transmission is made with the same angle as the old Walter V drive unit, so minimal alterations to the engine bed is required.

For Atomic 4 powered boats, Beta Marine offers this engine [and 3 smaller engines] with compatable engine mount spacing, so no stringer alteration is needed. This saves CONSIDERABLE time, money, and hassle.

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Letting an engine idle
I never have understood the problem with letting a marine diesel engine idle or run at low loads. Sam
[JED] The problem is, this activity is VERY HARMFUL to any engine. Check you car owner's manual. It will note that if the car is driven regularly on short trips, or idles for extended periods, the oil change interval must be shortened. This is because the engine is not allowed to reach operating temperature, where harmful combustion by-products are eliminated. This acidic by-product accumulates in the oil, where it chemically attacks the engine bearings.

Here's what happens when a diesel engine is idled:
  1. Timing gear backlash [gear rattle] is maximized, leading to increased wear
  2. The cylinders get glazed, leading to low compression
  3. The engine is run at below operating temp, leading to carbon accumulation in the combustion chamber, injector tips, piston rings, piston crown, valves heads, seats, and stems, exhaust manifold, turbocharger, etc. Carbon on these parts will lead to accelerated wear, and possible piston ring sticking and low engine compression.
  4. Also, the injected fuel gets past the piston rings, because the engine is not at the correct temperature, and dilutes the lube oil. This compromised oil is sent to ALL the engine bearings, where it increases bearing wear.
There's more, but isn't this enough to convince one that engine idling should be avoided?

Yanmar [for one] says not to idle their engines for more than 5 minutes. Bottom line on engine idling - it's great for the engine repair business.

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My Yanmar just stopped
I have a Yanmar 2GM20F. The engine started immediately and then after about 5 minutes at about 1000 rpm, while readying the boat for a sail, the engine stopped. I have not been able to start the engine since then. We immediately attempted to pump any air out of the fuel line at both the fuel filter and the injector nozzle as the Yanmar engine book suggests. What do I do now? Bruce

[JED] When a diesel engine stops as you describe, it's usually due to a fuel supply problem. Of course, there are other reasons for your engine's symptoms, such as - it burned a valve or blew out a head gasket, is loosing compression, or the fuel lift pump stopped working, etc.

I would first ensure that there is FRESH [less than 1 month old] fuel in the tank [consider filling a clean gallon jug with fresh fuel, and using that as a temporary fuel tank] and bleed the system, as the manual says. If no fuel can be bled, turn the engine over [engage the decompression device and crank by hand] one revolution, and try again. If no fuel now appears, replace all fuel filters, and try bleeding again. If again no fuel, you probably have a non-working fuel supply pump, or restricted fuel hoses, or an air leak somewhere before the supply pump. If fuel does appear, proceed as below -

Now, leaving all injector line nuts loose [on the injectors themselves] set the fuel control to max [full speed] engage the decompression device [it will have to be tied to the engaged position] close the sea-cock [to avoid flooding the wet muffler, & the engine] and crank the engine. It will crank fast, as there is no cylinder compression for the starter to overcome.

BE CAREFUL! as fuel under this high pressure can act like a syringe, and be injected through your skin. I place a CLEAN rag over the nut to avoid the problem. Now crank the engine for 10 seconds and check the rag. If there's no fuel on it, try bleeding the system again, and cranking again. If no fuel, there may be a fuel system leak somewhere BEFORE the fuel lift pump, that is allowing air into the system. Old fuel hoses are the prime suspects, as are banjo bolt copper washers and old Racor filter O-rings. If fuel does appear, tighten all injector nuts, disengage the compression device, open the sea-cock, set the fuel control to 1/2 max speed, and try starting the engine. It may huff and puff a bit, and run rough, which means the injector nuts should be cracked [loosened] one at a time, then tightened, to bleed the injection line and injector. Place a rag over the nut, to avoid injury. Use "Brakleen" to spray the spilled fuel off the engine, after placing an oil absorbent pad under it. This avoids the fire hazard.

If there is a further problem, you may need a mechanic on site.

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How should I replace the fuel pickup
I removed the pipe that screws into my fuel tank that carries fuel to my engine. It is an aluminum tube that is just long enough to stop short of the very bottom of my tank. I've heard that this thing can cause trouble; what should I check before reinstalling it? Andy

[JED] The fuel tank standpipe that's located inside the fuel tank should be removed and closely inspected where it's attached to the threaded fitting. You can pressurize it underwater to check for bubbles. What can happen is this - as the boat is sailed, the fuel sloshing about in the tank will attempt to break off the aluminum tube. It can cause a very small crack as the metal work hardens. Should this occur, air will be introduced into the fuel system, and the diesel engine will stop. It can sometimes manifest itself by the engine working fine in calm weather but when the waves build, the crack becomes active, and the engine stops. It can drive you crazy trying to figure out the problem. You can reinforce and seal the area with an epoxy fillet. I remove the standpipe completely and install a hose barb, using epoxy. This leaves a very short lever arm for the fuel to work against, and is very strong and crack resistant. The standpipe is eliminated and replaced with fuel resistant hose that lays along the bottom of the fuel tank.

I would be cautious about having the pickup tube so long that it "lays along the bottom...". The original design idea of the "standpipe" is to deliberately be a little short of the bottom of the tank so that if you do get water in the tank, it wont be sucked into the pickup tube. Andy

[JED] Your observations are correct - that's how the ORIGINAL design was built. However, it has been learned over the years that instead of leaving a layer of crud on the tank's bottom, as the original design does, it's preferable to remove that crud before it accumulates and contaminates the entire fuel supply. The newest design, as described above, continually draws fuel from the bottom of the tank, where any water and crap can be removed by the primary fuel filter, keeping the fuel supply clean. This method also ensures that when the weather gets rough, there is no layer of crap to be suddenly mixed with the fuel that can overwhelm the primary fuel filter and stop the engine.

This is an example of why, when rebuilding/restoring a boat, it is VERY IMPORTANT to not just duplicate the old systems one finds, but to use the opportunity to upgrade the vessel and her various systems to the newest standard. This is just one instance of when hiring a professional mechanic as a consultant can save you lots of wasted time and aggravation.

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What's the price to repower my boat?
I am repowering my boat and pricing several different engine brands. Please give me your best price.

[JED] If you are buying an engine strictly by price, you will buy a competitor's engine. However, if you are buying according to best value, we are confident that your choice will be Beta Marine. Our engines are the most the technologically advanced on the market today, which means they run quietly and smoothly, with minimal exhaust emissions. They are also very compact and lightweight for their output. All maintenance points are very acessible, so it's a pleasure to work on the engine. The dipstick, oil filter, fuel filter, fuel lift pump, fuel bleed screw, raw water pump, zinc, and heat exchanger core are designed with easy service in mind. An oil change pump is mounted on the engine, making this messy chore a breeze.

Spare engine parts are available at any Kubota farm tractor dealer, at a considerable savings, especially when compared to our competetion! You will pay "farm tractor" prices, NOT " marine" prices.

Beta Marine engines use glow plugs as a starting aid, so the engine will start when the outside temperature is well below freezing. The raw water pump is a common Jabsco unit, with spare impellers selling for $20. The entire pump can be purchased new for under $200. [try that with Yanmar!] We supply you with the Napa automotive and Kubota part numbers for the oil and fuel filters, V belt, etc., so you can shop locally for these maintenance parts.

Best of all, our engines have a proven track record for reliability and economical operation, with engineering second to none. Kubota is the world's largest builder of industrial diesel engines under 100hp. They power forklifts, backhoes, industrial dewatering pumps, emergency lights, irrigation equipment, generators, mining equipment, Bobcats and a wide range of construction equipment.

If you are replacing an old Atomic 4 gasoline engine, we have 4 different HP engines [10hp, 13.5hp, 20hp, and 28hp] that are available with Atomic 4 engine mounts at no extra charge.

We also offer white Awl Grip paint, remote oil filter mounts, custom engine mounts [if you need them], a 70 amp alternator and "smart" controller for the 20hp engine, 100 amp alternators and smart controllers for the larger engines, water heater fittings (so the engine can heat domestic water for showers and cooking) and a front crankshaft PTO, to drive a watermaker, refrigeration compressor, bilge pump, etc. There are also several different types and brands of transmissions available to suit your particular application. In short, Beta Marine engines add value and utility to your vessel, at a reasonable price.

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How can I change oil easier and without the mess?
Is there a better way to change the oil filter on the Westerbeke W27 without oil going everywhere? I have tried cut off plastic cartons and plastic bags under the filter but since it is horizontal and the access is limited the oil is hard to contain. Any way to relocate the oil filter for easier access and mount it vertically? George

[JED] This is commonly done. I supply remote oil filter mounts for many diesel engines, and install them in a wide variety of boats, both power and sail. An upright [vertical] oil filter has many advantages, such as:
  1. Minimal or no mess when changing oil filters.
  2. Use of high quality, readily available oil filters that are usually MUCH cheaper than the engine builder's filters.
  3. Option of installing a larger oil filter, thereby increasing filtering capacity.
  4. The filter can be filled with oil before installation, so the engine bearings are not oil starved upon engine startup.
  5. Convenience, as the oil filter can be mounted on a bulkhead, or below the cabin sole.
  6. No oily bilge problem or discharging oily water overboard when the automatic bilge pump operates.
Beta Marine has recognised the above advantages, and now offers remote oil filter mounts as an option on all their new engines.

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