Diesels - Time to overhaul?

gstraub · #1 11-23-2002

An engine mechanic I am not, so I have this question. I''m looking at the potential purchase of a boat. The inboard diesel, a Westerbeke 40 HP, has about 4,000 hours on it. I will have it inspected if I get serious, but owner claims good compression and no smoke or oil burned. I still think 4000 hours is a lot and that I am looking at at least an overhaul in the very near future. Any mechanics out there that can give me the typical time between overhauls for an engine of this size that has been maintained?

Gerhard

Peter_pan · #2 11-23-2002

Hi
You may compare hours to miles. Consider One hour at 60 miles per hour = 6000 miles. Hours only indicate that the engine is running. It doesn''t take into consideration idleing and low rpm. The clock just knows that the motor is running. I have 8000 knotical miles on my boat and it traveles at 10 knots. these are gas engines and are no way needing an overhaul yet.
Jim

walt123 · #3 11-23-2002

4000 hours is nothing on a well maintained diesel. Even "Modern" high speed pleasure boat engines should get up to 10000 hours. Maintain it properly and it will serve you well.

acmecoyote · #4 11-23-2002

Not sure how you would judge a engine from a boat to a vehicle, but this is the best I can come up with. Genrally you can see atleast 300,000 - 500,000 miles from a diesel in a truck. Most the time more. But this is when I would not hot dog it anymore,just taken it easy. 400,000miles - 500,000miles / 60mph = 5000 hours - 8300 hours

But I have come across several boats that have had 9000 - 10,000 hours on them. They would be the ones I would more than likely rebuild if I where to buy. Anything under 8000 hours, I would not worry about unless you just a getting poor performance from it in burning oil, fuel, or drop in rpm when running.

hamiam · #5 11-25-2002

4000 hours on a diesel is not necessarily alot unless the engine was either not maintained properly or used extensively at low rpms to charge batteries, etc. If the engine is a rusting hulk, emitts black, blue or white smoke, and/or is lacking in power you may have a problem. If you get serious you can hire a diesel surveyor or diesel mechanic to run some tests and give you an opinion.