[Sunphish]

I am considering the purchase of a boat (1980) that has a 1 gm Yanmar. I believe it to have been primarily a fresh water boat, now in saltwater. I also believe it has had the best of care by it's current owner, with many new parts, but not a rebuild.

Here is my concern. Nothing mechanical lasts forever. 35 years has to take it's toll on the internals of any engine, even one that is well cared for.

Best case scenario, how long will this gem hold up, before replacement is likely?

5yrs, 10, 15?

My inclination is to give the value of a 35 year old engine as very minimal. But I am no expert so that's why I'm here. Thanks for any guidance.

 

[aa3jy]

To many variables but the number of hours on the engine doesn't tell how the engine was operated;ie; long continues hours, short runs barely enough for the engine to get to operating temps....

If concerned suggest to get a seperate engine survey along with the typical boat survey.

 

[bljones]

an engine survey, or at very least a wet/dry compression test and mixing elbow inspection wouldn't hurt. They are a tough, durable little engine, and are easy to repair, with decent spares availability.

 

[westsailpatti]

We have a 2qm15 , it's a 79' model we are sneaking up on 1,000 hrs. it has always had a fresh coolant and salt heat ex changer . One problem it's always had is low oil press when it gets up to temp ,it only gets like 10 lbs. @ 2,700 RPM and 2 lbs. @ idle . I use Lucas oil treatment and that helps a lot . We have been dealing with this engine for over 20 yrs. I always say if it gets terminal will just have it re built . Bit of caution though some parts are getting hard to find .

 

[Bill-Rangatira]

We have a 2qm15 , it's a 79' model we are sneaking up on 1,000 hrs. it has always had a fresh coolant and salt heat ex changer . One problem it's always had is low oil press when it gets up to temp ,it only gets like 10 lbs. @ 2,700 RPM and 2 lbs. @ idle . I use Lucas oil treatment and that helps a lot . We have been dealing with this engine for over 20 yrs. I always say if it gets terminal will just have it re built . Bit of caution though some parts are getting hard to find .

good to hear about your 2qm15 i am about to put one in my boat

 

[PaulinVictoria]

Best case, thousands of hours. Worst case, thousands of dollars.

 

[Capt Len]

Real oil pressure test for start and at temp tells about lower end.Compression test dry and with a squirt of oil on the rings tells about the rings and valves Smoking and leaks are visual .Most else is visual too and cheaper to deal with. A great exciting learning experience no mater what.

 

[sony2000]

From my observations 50% of them fail from owner error. Overheating, poor winterization, and low oil. Other than that, 2-3,000 hours of running will wear them out.

 

[BarryL]

Hey,

IMHO most marine diesels wear out from the salt water environment than from mechanical use. A diesel that is treated to basic maintenance will run for many thousands of hours. A diesel that is exposed to salt water can be worn out in 10 years. I've seen things like oil pan rotted from salt water, then the oil leaks out, then the engine is junk. Same thing with exhaust manifold - it gets plugged from salt / scale build up, then the engine overheats and the head gets warped. IMHO those are NOT an oil problems or cooling problems - that's a poorly maintained engine.

I would be scared of a raw water cooled engine in salt water. I would be afraid of the internal water passages and just about every part of the engine. Inspection will be very difficult. I don't want to scare you but as you guessed, it's impossible to tell.

My last boat had a 1986 Universal Diesel M25. I bought the boat in 2006 with 3500 hours on the engine. I sold the boat in 2014 with about 4000 hours on it. The engine ran great, make good power, ran nice and cool, etc. During my ownership. I had the heat exchanger cleaned out, the exhaust manifold changed, changed the raw water pump, and did most other basic maintenance. The oil pan was showing signs of rusting, otherwise the case seemed fine. The hardest part was keeping the engine clean, the electrical connections tight, dry, and clean, and that stuff. Otherwise change the oil once a year, keep the fuel clean, and don't worry about it.

Barry

 

[SloopJonB]

We have a 2qm15 , it's a 79' model we are sneaking up on 1,000 hrs. it has always had a fresh coolant and salt heat ex changer . One problem it's always had is low oil press when it gets up to temp ,it only gets like 10 lbs. @ 2,700 RPM and 2 lbs. @ idle . I use Lucas oil treatment and that helps a lot . We have been dealing with this engine for over 20 yrs. I always say if it gets terminal will just have it re built . Bit of caution though some parts are getting hard to find .

If you've always had low oil pressure I'd suspect the sender or gauge rather than the actual pressure - have you ever checked them?