What would you do with a (pretty) good running 29 Year old Diesel?

[ftamburrano]

Continue doing regular maintenance following manufacturer's instructions. After removing and cleaning the fuel tank, start normal use of two additives: one bactericide (you choose) and one water dispersant, to add regularly when you fill up the tank. The problem you described is due to bacterial growth. Bacteria grow up and multiply in presence of water; water builds-up when the reservoir "breaths" being almost empty, with normal temperature variation (expansion-shrinking) inside. Combining water dispersant and bactericide, you get rid of the muds due to bacteria multiplicating, dying, etc. I had this big problem for years, then discovered the cause, now removed. I have a 1989 Volvo-Penta 2002. Those made at that time were the best arine engines, without electronics. It is sufficient to have a lightning at 500 meters distance from your boat, and electronics may finish functioning. You must not have an engine with electronics in high seas! Remember. Ciao

[sinnerman]

Overlooked diesel maintenance items:

-Adjusting the valve clearance (lash)

Periodically removing the fuel injectors and taking them to a good diesel shop to inspect:
-The spray pattern
-If they are firing (cracking) at the correct pressure
-That they do not drip (leak) after firing [not good for the engine...]

I would also recommend that while the injectors are out, run a compression test (make sure to turn off the raw water intake to prevent flooding the muffler) to verify the engine's "health". [Like a trip to the cardiologist]

My Example:

My OLD boat has a Universal M25 three-cylinder diesel. It starts "OK" and it produces NO smoke (white, black or blue), other than a little whiff of blue smoke at startup.

However it vibrated somewhat and had "pinging" or "rattling/railing" which I understood to be an indication that the injectors were not fully seating (leaking) after firing causing the cylinders to fire randomly.

I ran a Liquid Moly "Diesel Purge" though the pump & injectors to see if it might help but it didn't.

I then pulled the old injectors.

The injectors had been on the engine SO LONG that I fought for about two hours to free up frozen two connections. One had to be broken with the the injector line clamped in a vise...

I took the removed injectors to a diesel injector/pump shop to test them and all three had problems.
-Two were not sealing after firing and were dripping fuel
-The one not leaking was just squirting liquid fuel in a sideways stream
-All three had pressure settings too high for the engine (maybe the wrong p/n injectors installed)

With the injectors out I ran a compression test. The results startled me as the # 1 & 2 cylinders had pressures well below the minimum spec of 327 psi. (tested: 260-280 psi). [Note the New engine spec is 412-469 psi!!]

I then removed the valve cover and checked the valve clearance (lash) with the engine COLD.

Only ONE of the six valves had an adjustment in-spec. The exhaust valves had almost zero clearance on two valves and one intake was more than double the high end clearance.

I re-ran the compression test after the valve were adjusted to spec and the unfortunately compression on 1 & 2 was still low, so I suspect I have either some burned/improperly seating valves or a leak in the head gasket between 1&2.

I installed three brand new OEM (Japan) injectors purchased at a Kubota dealer (1/4 the price of Westerbeke-Universal) and the engine now idles much smoother with less vibration (even with the low compression).

MORAL of the Story:

These little marine diesel engines are extremely tolerant of problems and will still appear to run "normally" even if they have internal issues.

Per a Mercedes mechanic (Mercedes source on YouTube), leaking / poorly firing injectors are one of the worst things for the life of a diesel engine.
https://www.youtube.com/user/Mercedessource

If the valves had been adjusted properly as a maintenance item, my compression would probably still be OK.

Per the Universal M25 Service manual, they recocomend checking the injectors and adjusting the valves once a year.

Sorry - Long winded..

Cheers

[ftamburrano]

Sinnerman,
you made a very good report. A good lesson. Important, as I said in my comment, to follow manufacturer's recommandations regularly. Valves clearance is important, and changes by itself while running, often. All you gays, keep your old engine as long as possible. Goog navigations!

[sv_isara]

So to check valves, I need to remove the valve cover gasket. Think I can re-use the gasket?

[Wotname]

^^ often but not always. Depends on how many times it has already been re-used and how it was last applied.

What make/model engine?

[CarlF]

Think about replacing anything made of rubber. Start with the mounts that loose their elasticity after 15 years (you wouldn’t drive on 20 year old tires). The boat will be noticeably smoother under power.

A burst hose is no fun at sea. At a minimum go over them replacing any with cracks, bulges, or hard spots. Look especially carefully under the clamps. I replace any hose below the waterline at 10 years. If it breaks at sea with the seacock open it’s likely that you’ll have serious salt water damage to the wiring before you notice it and get it stopped.

[Nicholson58]

Originally Posted by boatman61

If it ain't broke don't fix it..
I'd get your fuel tank sorted out though were I you.

It’s not the engine.

Clean or replace the tanks. If there are no inspection ports, add them.

Pay for a total clean. Dump the old fuel.

Add a fuel polisher.

Check the deck port O-Ring. Number one source of water in tanks.

Keep them clean and water free and don’t use additives.

[Dieseldude]

Lots of great tips given here. Could be handy to keep a stock of new gaskets for the most vulnerable ones such as oil pan, valve cover, and front cover. If the shaft seals are not leaking, probably no point in touching them until you see them weeping. Front seal would be quite easy, but uncoupling the gear box for the rear would be a big job. Old seals will eventually start seeping sometime, so would be good to have spares on hand. For minor rubber seal leaks, some AT-205 added to the oil might help. https://atpautomotive.com/featured/re-seal#!prettyPhoto


Modern low sulfur diesel has less lubricity than old time diesel. Use of an additive such as Howes would provide some protection against fuel pump, injector, and upper engine wear. https://www.howesproducts.com/products/diesel-treat

[sail sfbay]

If the original post plans to remove and dispose up to 40 gallons (fuel tank capacity) of old diesel, be aware of the regulations to safely dispose diesel in fit-for-service diesel fuel containers. Find out more from the California county of residence. I know because I recently disposed 5.5 gallons of diesel fuel in Napa Couny https://naparecycling.com/residents/...0the%20details. Alternatively, the fuel can be polished, albeit there is only one marine diesel fuel polishers in the San Francisco Bay. I know becauseI had 2 boats diesel fuel polished by Marine Lube out of Alameda: Welcome to Marine Lube

[argonauta1]

First off at only 3400 hours it is still in its infancy. The 1993 vintage YANMAR 4JH-2E in the vessel we circumnavigated in now has over 9000 hours and still runs well. It has always had regular maintenance, never run short of oil or coolant, never over heated, never over boosted and never run at full power or at less than 1500 RPM when underway. Take care of your infant and it will give you many more thousand hours. Essentially unless abused or neglected, Yanmar diesels seem to run forever.

[Carl-T705]

Even the old abused YanMar engines run a long time, have a QM 15, seems like the only thing worn out is the paint job.

[Nicholson58]

Our Westerbekes, generator and main, are 44 years old. Start instantly and run well. The only problems we have had are fuel systems related. I had to dispose of 180 gallons in Trinidad last month due to gels etc appearing in the fuel. My mistake was keeping all 300 gallons of fuel tankage in play, four tanks, so that after many years the fuel was deteriorated. Tot enough turn over. This overwhelmed the polisher. We had a commercial fuel system company handle it. It was less expensive to replace fuel than to try to clean it.

[rossdv8]

Originally Posted by stormalong

. . . change the oil religiously, . .

I do that with my old Toyota HiAce diesel.
While I'm changing the oil, I pray that nothing breaks for another 400,000 or so kilometres!
Sadly, my yacht engines have all been petrol and don't respond to the same care :-(

[lituya1617]

A Yanmar marine diesel built 30 years ago has no fixed life expectancy. If you run it hard every few hours and run it regularly, keep quality fresh oil in it with oil changes at around 200 hours, use good filters with internal bypass valves, do all the routine maintenance tasks, have a good set of alarms to tell you if something is too hot or low on pressure, and lay it up properly in off season, things will wear out but the engine itself will not - in your lifetime. Now, are there some things you can do to make these engines last longer? Yes, and some of those things are seldom done but, I think, important. I cannot mention them all due to space here, but my pet protect-the-engine idea comes from overhauling Yanmars with water-lift mufflers/wet exhaust systems. I suggest that the engine be protected by removing the exhaust water-injection elbow whenever it will be out of service for more than a week or two. And I also suggest that the engine be cranked over a couple of times (not started) after the exhaust elbow is pulled away from the manifold. The reason for this is that the water in the exhaust is going to vaporize and rust the head in the idle engine - quite seriously over time. I have had to replace heads because of this engineering flaw - a flaw common to all heat exchanger wet exhaust systems.

[kmacdonald]

A commercial crabber near me just replace a Cat 3208 with 34,000+ hours and it still ran well.