How long will a Yanmar 20hp last?

Zagato

Zagato

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I am looking at a boat which has it original 1997 Yanmar 20 HP in it. It has a readout showing the hours it has done (unfortunately I haven't been able to view the boat or read the display yet!) how long do you think it will last.

Will it be a case of new engine or get it reconditioned? Think they are about 3k new :rolleyes:
 
About the same length as a piece of string! It's entirely dependant on how well it has been looked after & how hard (or not) it has been used. Lack of use can be more damaging than hard work, but proper maintenance is the most critical factor.

My Volvo MD2B lasted 35 years but I know of much older ones. Just take a good hard look at it see how it starts & runs & the general condition of the ancillaries. 1997 is recent, I wouldn't expect to need to replace that for some time (ie a few years to decades) but condition is far more important than age.
 
How long is a piece of string...........It depends on so much, & how it was used and serviced. There are many yachts with engines a LOT older than that , giving sterling reliable service, the Volvo in my late Jaguar was from 1978 and perfectly reliable, and that is not exceptional.
Superficially, I would relate to your Yanmar as a "new" engine, as I do my 1989 2GM. I have also seen several engines of this age that were in a terrible state: but it takes a helluva lot to make a diesel untenable. Most marine engines are UNDERused, and that is probably what does more harm than anything.
 
How about 3000 - 5000 hours minimum unless badly neglected but possibly much more that if looked after carefully.
 
My less than scientific answer is, if it's been used regularly and basic maintenance carried out, a bloody long time.

The V8 in my previous boat was the original 1982 engine and on survey when I sold her, 3 years ago, she apparently was the nicest one the surveyor had seen.
 
These engines are pretty robust. As long as the mixer elbow on the exhaust has been regularly replaced, the engine will be fine. Corrosion in the elbow allows salt water to get into the exhaust manifold and thence into the heads. Heads have been known to fail when this happens.

My own engine, a 1GM10, is over ten years old. Last winter I gave it a top end overhaul and it's as good as new. I had a problem getting the injector out and in doing so damaged the pre-combustion chamber. Even allowing for the cost of new engine mountings, it was far cheaper than re-engining.

If the engine runs and doesn't make smoke or rattle and the gearbox operates, I guess you'd be fine. Check the alternator and the wiring, make sure the belt is fine and there are no obvious oil or fuel leaks. A top end overhaul for the twin would probably set you back around £200 for parts. I had the starter motor and alternation done by an auto electrician for £40, and the injector and pump done for another £80. If you're thinking of paying a marine engineer to do the work, add another £300 ish. If you've doubts about the engine you could aways pay for an inspection report by a marine engineer along with your survey.
 
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Mines is an 86. It's had a new cylinder head though after a leak from the exhaust elbow and water entered the head.All before my time. If it's running alright just now I would have a good look at the elbow as they are prone to corrosion problems. It should really have been replaced by now.
 
The engine is lifed for over 8000 hours - over 50 years of normal yacht auxilliary use. Have seen some on charter boats in the med with 12000 hours on them.

Things to watch are cooling systems, exhausts and electrical connections, all of which have a hard life with constant stop, start and short runs. Run it hard, typically 2500+, make sure you get it up to full working temperature every time you use it, change the oil and filter every 150 hours or each year and the basic engine will outlast you.

BTW latest engines are at least 50% more than you guessed, so look after it.
 
Many thanks for the replies, the boat has been well looked after, all new standing/running rigging last year, sails valeted annually and the engine serviced annually. I will find out if the mixer elbow has been done and what the hours are tomorrow. All sounds good...:D
 
Zagato said:
Many thanks for the replies, the boat has been well looked after, all new standing/running rigging last year, sails valeted annually and the engine serviced annually. I will find out if the mixer elbow has been done and what the hours are tomorrow. All sounds good...:D
Click to expand...

One other thing if it's a 2gm20 it's actually only rated at 18hp max
 
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Zagato said:
I am looking at a boat which has it original 1997 Yanmar 20 HP in it. It has a readout showing the hours it has done (unfortunately I haven't been able to view the boat or read the display yet!) how long do you think it will last.

Will it be a case of new engine or get it reconditioned? Think they are about 3k new :rolleyes:
Click to expand...
Assuming that the engine is the 3GM20.

If raw-water cooled between 5000 - 10,000 hours.

If indirect-cooled 8000 - 12,000 hrs.

As already said the big variable is how well it's been maintained.

The 3GM20 has been discontinued - a complete rebuild, rebore etc will cost about £1750 for parts - double that to include labour.
The replacement is the 3YM20, these can be shoehorned into the same space and are about 18% more powerful and cost about £3750 if you shop around - fitting about £180, excluding ancillaries such as water-trap, anti-siphon etc.

I did the exercise about 3 years ago.
 
Yanmars are great engines, but parts are so expensive; In the past I replaced old engines with Yanmars and I like the fact that they are purpose made for marine and are light and compact. If the engine is made in 1997, it is still a baby.
 
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