Southace,
are you talking engine life or time between major service.
Remember they are diesel engines and looked after will go forever.

yamaha 9.9 4stroke outboards do 6000 hours before you throw them away

An engine should be replaced or rebuilt when it no longer performs the functions of an engine, not when it reaches a certain number of hours. It it leaks oil faster than you can pour it in, or blows so much smoke the EPA follows you around, or rattles like you just dropped a draw of cuttlery then do something about.
If it aint broke don't fix it.

In another life I used to sell boats and work in a marina.

Regarding usage, we used to expect an "average" owner to do about 50 hours a year.

A heavy user, that was out at least weekly, sometimes more, could go up to a 100 hours/year.

It used to average out pretty well over the years and ages of boats.

Of course this would not apply to live aboards, or boats coming back from cruising/circumnavigation etc.

Most yacht engines die from lack of proper maintenance and under usage rather than high engine hours.

Driving a car at 100 kmh for 1000 hours puts 100,000 klms on the vehicle so therefore 1,000 hours on a yacht engine could be compared to 100,000 klms on a road vehicle.

But we are talking diesel engines which are good for at least twice the usage of a petrol engine plus the hour meter on a yacht engine counts the hours it has the engine panel switched on no matter the revs it is running at or if it is running at all.

I would be more concerned about a low hour declared engine with no maintenance log than a high hour engine with a documented maintenance history.

With a marine diesel engine 10,000 hours of running is nought to be concerned about. The service log is what you should be concerned about.

I have owned two yachts both with diesel motors, both have given me grief at times. I have worked many years in boat yards and seen many Diesels getting replaced with new. I have spent the past two years on driving a loading barge with new Yanmars and two years driving a sports boat also with a new Yanmar. why wouldn't I ask the question? Just cause they teach you at marine collage diesels should run for ever the fact seems to me they do wear out and need replacing over time. its such a old school way of thinking.

southace said..

please just remind us again why your old diesel is not running at the moment and why your not out sailing? Perhaps repairs? Haha

It is not running because I am doing the correct maintenance on it that the previous owner failed to do.

Some of it is "Planned maintenance" which may be a concept foreign to you or what you might call "Old school thinking".

One of the things that separates man from the animals is the ability to think of the future.

I just wanna go sailing too but my sailing WILL be trouble free because of my forward thinking and the actions I do today.