40 year-old Yanmar

[Michigan_Eric]

I am considering purchasing a 1982 C&C with the original Yanmar Diesel. How do I go about evaluating the condition of the engine? It has no hour meter, so I can only guess as to how many hours are on the engine. The boat is on the Great Lakes, and I have been assured that it has only been sailed on the Great Lakes, so it has only been used seasonally, say 5 months out of the year.

Are there any statistics about "average" number of hours that an engine might be used in a season?

If I decide to purchase the boat I will of course have a thorough survey, including having the engine thoroughly examined. I take it that you can test compression, etc. without too much trouble.

As good as they may be, are Yanmars known for any particular issues? I don't know the model number offhand, I may get that and update this post if that helps.

When buying a boat with an engine of this age, what can be done to help it continue to be reliable? Replacing the fuel and water pumps (and keeping the originals as spares) seem minimal.

[Engine man]

What is the length of this boat? This will assist in determining what model Yanmar is installed.

Hiring a competent marine diesel mechanic that is familiar with that particular Yanmar is $ well spent. We do the following -

Find any maintenance records aboard, or contact the seller for same.

Visually inspect the engine, drivetrain and installation for condition.

If the buyer wants to proceed further, we suggest a sea trial, followed by a compression test. Joe

Originally Posted by Michigan_Eric

I am considering purchasing a 1982 C&C with the original Yanmar Diesel. How do I go about evaluating the condition of the engine? It has no hour meter, so I can only guess as to how many hours are on the engine. The boat is on the Great Lakes, and I have been assured that it has only been sailed on the Great Lakes, so it has only been used seasonally, say 5 months out of the year.

Are there any statistics about "average" number of hours that an engine might be used in a season?

If I decide to purchase the boat I will of course have a thorough survey, including having the engine thoroughly examined. I take it that you can test compression, etc. without too much trouble.

As good as they may be, are Yanmars known for any particular issues? I don't know the model number offhand, I may get that and update this post if that helps.

When buying a boat with an engine of this age, what can be done to help it continue to be reliable? Replacing the fuel and water pumps (and keeping the originals as spares) seem minimal.

[sailorboy1]

there are lot of threads here about "how long will engines last"

you will save a lot of time using the search

[RaymondR]

Those older engines are very durable and long lived. I removed a 3GM30 from my old boat when it was about 30 years old and replaced it with a larger diesel. We later used the 3GM to drive a hydraulic pump and I was surprised when the old motor was able to survive about six weeks of full throttle running and is about to be placed back into the same service again.

[grantmc]

It would assist to respond a tad more sensibly if the model of the engine was stated. But that aside. Raw water or heat exchanger cooling?

Assuming it is the original motor then it's 40 years old. Would you expect a 40 y/o car, with original engine, to go for much longer? Parts for old Yanmars are now very expensive, if even available. And I've yet to meet an engineer or mechanic able to predict with any real timing of the catastrophic failure of an engine.

And it's not so important about the hours (in my view), what is important is the regularity of oil and filter changes (some old Yanmar models don't actually have replaceable filters, you just turn a handle before changing the oil, so basically useless). And no one is going to tell you that, actually, I was really lazy and only changed the oil every year (or three).

General issues of concern on Yanmars include:

• head gaskets (in horizontal cylinder models)
• engine mounts rust and rubber ages badly as bellow. 10 years ago a set was $500
• water manifolds also difficult to source and expensive

I think too, a significant cause of damage to small diesels (that I witness all too often) is that owners just drive in/out of the marina and then shut their motors off. The engines rarely, if ever get to full operating temperature.

So if it were me looking to buy (and it's not) the C&C (lovely yachts by the way, especially nice line) then I would budget on another $15K to repower in the next 3 years. Budget doesn't necessarily mean do it.

[tkeithlu]

Engine Man speaks with wisdom. There is no reason to doubt the engine on age alone. Your first clue will be starting it and accelerating it. Hard starting? Black smoke? If it does the job without setting up a smoke screen, then you can follow with a compression check just to make sure.

I don't knnow how old my Detroit Diesel 453 may be. Love it. Replaced the 24v starter with a 12v. for convenience. 1,000 hours later with no repairs. Just change the oil and filters.

[Cheechako]

Originally Posted by Michigan_Eric

I am considering purchasing a 1982 C&C with the original Yanmar Diesel. How do I go about evaluating the condition of the engine? It has no hour meter, so I can only guess as to how many hours are on the engine. The boat is on the Great Lakes, and I have been assured that it has only been sailed on the Great Lakes, so it has only been used seasonally, say 5 months out of the year.

Are there any statistics about "average" number of hours that an engine might be used in a season?

If I decide to purchase the boat I will of course have a thorough survey, including having the engine thoroughly examined. I take it that you can test compression, etc. without too much trouble.

As good as they may be, are Yanmars known for any particular issues? I don't know the model number offhand, I may get that and update this post if that helps.

When buying a boat with an engine of this age, what can be done to help it continue to be reliable? Replacing the fuel and water pumps (and keeping the originals as spares) seem minimal.

-Testing compression on a diesel requires a fitting. So it ain't just simple. If you have a mechanic that has a Yanmar fitting that would help. (pressures are too high for hand held gages)
-Evaluation:
-Does it start right up when cold?
-Watch the exhaust at start up; many will smoke a bit at first ....but does it stop and not have black or blue smoke?
-Older GM series Yanmars can have cracked piston issues. I had two 3GM30's and both had an issue before 2500 hours. They started slowly/poorly with those issues when cold. Once running it was a bit difficult to tell.
-Engines used seldom can be as much an issue as those used a lot. But that is aggravated in salt water use. Being a fresh water engine is a big plus, especially if it doesn't have fresh water cooling system.
-Check dip stick after running for bubbles indicating water in the oil.
-Check the coolant tank (if fresh cooled system) for oil after running.

Sometimes you just gotta go with your gut. if it isn't a rust ball under there, starts readily, doesnt smoke much once warmed up, that's a good sign. You can load and test a diesel pretty well just tied to the dock in gear at 1500 rpm or so.

[maine50]

The larger C & C's had 3qm30 Yanmars. Big top heavy (570lbs) diesels built for fishing vessels per talk w/ a dealer. Some were fresh water cooled, some raw water cooled. I sold a C & C 38 about 10 yrs ago and a fresh water pump pump was almost impossible to repair.

[hjohnson]

The Yanmar 1GM10 in my Ericson 27 was installed in 1983, so is coming up on 40 years old. Compression is getting a little weak, so harder to start on the winter (no glow plug either), and she’s started to sip engine oil. We figure we have another couple of years before we are faced with a repower. (We’ll go with a Beta 2 cylinder when that happens).

The biggest thing to keep an eye out for on the small Yanmar engines is compression, and raw water issues related to their exhaust (manifold and wet elbow). Other than that they’re pretty solid.

[skipperpete]

Hi Michigan_eric, the easiest test on an engine to get a fair idea of what its like regarding compressionis to take the oil filler cap off while the engine is running and observe the “blow by”, properly called crankcase pressure. If you see a lot of smoke or air coming out it often means the rings or cylinders are worn but can also suggest a blown head gasket to the pushrod gallery.
I’m not a big supporter of compression tests and prefer to do a cylinder leakage test... but often do a compression test as well while the gloplug or injector is out.