Engine Hours

[jmcdboater]

My wife & I last spent great times on Searay 280 in CC delta, out of Sacamento. We are planning to sell our home in next four years when i retire and buy a motor yacht, aft cabin, 42'-55' and live aboard. We have been looking at a lot of boats, thinking of buying something needing cosmetic help, we're pretty handy and enjoy doing it. My big concern is avoiding a huge mistake with buying a vessel with rotten engines..... How many hours is relatively safe for diesel or gas engines? How much does it REALLY cost to rebuild them? Is a rebuild good, or how do you know when you should REPLACE them? Thanks for the help......

[David M]

Hours do matter. But what also matters is engine maintenance. Without proper maintenance, an engines life can be shortened dramatically. A well maintained Diesel can last well over 10,000 hours. A poorly maintained Diesel can be on its death bed in less than 2000 hours, usually from inadequate oil changes or being over propped where the engine was essentially lugged all its life and never reached a high enough RPM to have the carbon blown out of the combustion chambers.

What is going to tell you the condition of a Diesel are records of oil changes and a good marine engine mechanic who knows what he is looking at. You will also want to pay for an oil analysis. Given how expensive marine Diesels are, it is good insurance to hire one before purchasing a boat. Don't trust what yacht brokers or owner tells you. The broker is not on your side. He is only in it for the commission.

Whether to buy new or rebuilt depends on a number of things. I went through this about four years ago and decided on new because the newer tier two engines are much cleaner burning, are more efficient and have a number of nice features. You can buy rebuilt Diesels or if your are mechanically inclined rebuild one for yourself.

[hellosailor]

For a marine diesel, properly operated and maintained, 5,000-10,000 hours between overhauls might be normal. For a gasoline engine, 1000-2000 might be.

But a lot depends on how it was used and maintained, and whether it was raw water cooled or closed cycle. If the boat needs work, odds are the oil wasn't changed on schedule either.

In any case you'd want an engine mechanic to come out and inspect the engines. Take an oil sample and send it out for analysis as well, that's about $25 but can tell you if there's invisible bearing wear, etc. and trouble to come. A normal survey does not include any real examination of the engine condition.

[Cheechako]

You are likely talkng 2 big diesels in a boat like that, so it's very important you have inspections focusing on those engines. Some rebuilds work out great and some engines have issues that dont allow rebuilding. Also, beware of very low hours engines, sometimes non use can be harder on an engine than more use! In general terms you can compare as if it were a car: every 500 hours of engine use = 20-25000 miles. So a 2000 hour engine is like a 80-100,000 mile car. Commercial boats may get 10000 hours on an engine like Taxi's do, but that's because they are never shut off except for service! I think it's pretty rare to see a pleasure boat with a working diesel over 5000 hours. Not unseen, but rare-ish.

[maxingout]

I have 4500 hours on each of my diesels on my Privilege 39 catamaran. So far the engines have not had any major issues. I hope to get another 4000 hours before needing to do anything major. I do all the routine maintenance at specified intervals.

[David M]

Originally Posted by Cheechako

You are likely talkng 2 big diesels in a boat like that, so it's very important you have inspections focusing on those engines. Some rebuilds work out great and some engines have issues that dont allow rebuilding. Also, beware of very low hours engines, sometimes non use can be harder on an engine than more use! In general terms you can compare as if it were a car: every 500 hours of engine use = 20-25000 miles. So a 2000 hour engine is like a 80-100,000 mile car. Commercial boats may get 10000 hours on an engine like Taxi's do, but that's because they are never shut off except for service! I think it's pretty rare to see a pleasure boat with a working diesel over 5000 hours. Not unseen, but rare-ish.

True, many yacht engines rust out before they wear out.

[barnakiel]

An old and properly maintained/run engine is a better deal than a more recent one that suffered misuse and neglect. The trick is, when you are buying a s/h boat, it is hard to tell. A clean one is a good start in any case. If an engine looks like a heap of rust, it probably is just that.

I believe older diesels can live beyond 10k hours but I would expect the younger generation may not be that long lasting.

b.

[CSY Man]

There has been reports of Perkins 4-108 passing 15,000 hrs with no overhaul needed, pretty impressive stuff.

Hoping the same for mine.

[Dockhead]

Originally Posted by CSY Man

There has been reports of Perkins 4-108 passing 15,000 hrs with no overhaul needed, pretty impressive stuff.

Hoping the same for mine.

My father's boat, with a Westerbeke equivalent of that engine, had 9000-something hours on the clock when he bought it. Except the clock was broken, so nobody knows how many hours were really on it.

Or now. My old man has been to Venezuela and Guatemala and multiple trips to Cuba and the Bahamas in his 15 years of ownership. He mostly motors everywhere since that boat doesn't sail for s**t. That Perkins is just chugging along happily. I reckon it must have at least 20,000 hours on it by now. Spews oil everywhere but otherwise starts up and runs like a top. Great engines.

[cheoah]

Bought my boat with over 4000 hours on the Yanmar 3HM35F. The owner had meticulous handwritten records - was a german engineer type, and had replaced mounts, exhaust, etc at regular intervals. I did oil analysis and so far it runs very well. I'm convinced the high hours scared other buyers off. Pay for a good mechanic to go right through it (them). Would be a great investment.

[gonesail]

records? why would anyone look for records of oil changes? if anything you take the owner's word that he did it. were you thinking some mechanic gave a receipt with the hours on it? i doubt that.

[bobconnie]

Hours mean nothing !! Maintainence is everything !! Ask to see if the owner has records on the engine, oil changes, filter changes, rack and tune ups ect ! Some older 4 strokes will run for almost ever if taken care of ! as others have said, oil inspection, compression ck, visial inspection of engine for leaks ect! AND GET A GOOD Mechanic to inspect and make sure what ya are getting !! Just an old diesel mans 2 cents

[CSY Man]

records? why would anyone look for records of oil changes?

I record every oil and filter change as well as every other maintence operation performed. Does not cost much and could be of great value later;

[Cheechako]

Originally Posted by gonesail

records? why would anyone look for records of oil changes? if anything you take the owner's word that he did it. were you thinking some mechanic gave a receipt with the hours on it? i doubt that.

We are talking a large powerboat, likely with two diesel engines. many of these boats are serviced by professionals and have a maintenance log showing everything done. If you can afford $20k in fuel a year, you have someone else do the dirty work!

[David M]

Originally Posted by Cheechako

We are talking a large powerboat, likely with two diesel engines. many of these boats are serviced by professionals and have a maintenance log showing everything done. If you can afford $20k in fuel a year, you have someone else do the dirty work!

Yup, I have the yard do the oil changes when I get the engines serviced about once every 6 months. (I put a lot of hours on the engines each year) Proof of the oil change is in the yard invoice.