How Many Hours Will My Marine Diesel Last?

Often reading about Marine Engines, you can get conflicting information on how many hours an engine will genuinely last. Here's a couple of things to consider when taking in this information.

[@Jim.Thunda]

I’m in love with Gardener engines, let’s hear your opinions. Good channel, and well spoken without arm’s and um’s well done, your worth listening to.

[@BoatBuy]

Thanks Jim. Gardener are a fantastic engine with a solid reputation for reliability.

[@dieseldog00]

Buy a boat with a Cummins engine, run it at cruise speeds, do routine maintenance at right times and you should get at least 10,000 hours from that engine.

[@BoatBuy]

Depends which Cummins engine really!

[@charlesharper2357]

They did make some cheap engines for Dodge pickups that were a bit questionable...make sure it wasn't designed for a light truck.

[@100pyatt]

10k easily with good maintenance, synthetic oil and low-moderate cruise RPMs

[@deeremeyer1749]

What is "full throttle"? High idle - maximum governed no-load speed? Or full load speed? The loaded speed and condition for "max power"? Or peak torque overload i.e. the engine "lugged"? "Recreational" engine "ratings" are useless for all but "throwaway" engines like "marine" Cummins 6BTAs.

[@jimminyxmas]

Question: do you know the service life of those giant 16 cylinder mtu marine deisels that they fit into custom sportfishing yachts? Just curious as to when it makes sense to replace them as opposed to refit them. Thanks.

[@BoatBuy]

Service life for example on a MTU 16V2000 is 6000 hours before a major strip down and rebuild. At the higher horsepower ratings they’re only supposed to be operated at

[@100pyatt]

More like 60,000 hrs not 6,000

[@andydempsey7297]

Hi Aaron. Love your videos. I'm a brand spanker, just getting into boating, I want a live aboard boat to slowly improve it. I have a chance of a Gallart 11 MY 2000 going very cheap the reason being it was submerged on a slipway in Spain and the engines dont work and it needs the electrics sorting. The engines are Catterpillar 320 cv Diesels are they completley F###ed or could they be restored? keep the videos coming. Thanks.

[@BoatBuy]

Thanks Andy. I would say there is a high chance engines are completely f***** if they’ve been left and still aren’t running. With submerged engines, it’s important to get them running ASAP and the longer you leave it the less chance it will run. Sometimes a “cheap” boat is disguised as a really expensive one! I’d get quotes to replace the engines, but it would still be important to check the structure of the hull is OK, and the extent of sinking before even going down that path.

[@andydempsey7297]

@@BoatBuy Thanks Aaron, I'll give it a miss, keep the videos coming.

[@joshuagosine9540]

really great topic 👍🏼 but video is too short and I think a lot of info is missing, maybe some comparisons between the brands lie CAT and others. In your conclusion I would have liked to now how long a diesel engine would last if properly maintained etc, but nevertheless thanks.

[@BoatBuy]

Noted! Will keep making videos as time permits. Thank you!

[@BoatBuy]

No worries Joshua - I'm always working on content but will try and get to this eventually!

[@louv4437]

What are the most reliable marine Diesel engines? Thank you

[@BoatBuy]

Bit of a tricky one... one would say how long is a piece of string. Each diesel engine has a rated life span, some longer then others. Will depend on the size of the engine and how much HP it is putting out.

[@louv4437]

BoatBuy thanks for the response. As far as overall brands? Just like an general overview? What would be your top 5 marine Diesel engines on brand reliability?

[@BoatBuy]

@@louv4437 I quite like MAN, Cummins, Caterpillar, Volvo and Yanmar.

[@louv4437]

BoatBuy thanks so much for sharing that!

[@louv4437]

BoatBuy not a fan of Detroit bud?

[@izaacbanks3337]

Are engines derated by reducing the max fuel? Or is a smaller prop that will never load an engine to its max HP? And therefore derating it's hp I know ford Lehman's are rec rated to 120hp and 80hp for commercial

[@BoatBuy]

Nah, if you put a prop that won’t load the engine it will over rev. Usually injector/fuel pump/turbo adjustments