looking to buy a sterndrive diesel engine?
mannyslv asked:
looking for an engine between 100 and 150hp, this would be for a 20ft boat, what would be the best model? but im looking for sterndrive diesel.
thank you.
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looking for an engine between 100 and 150hp, this would be for a 20ft boat, what would be the best model? but im looking for sterndrive diesel.
thank you.
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Cummins/Mercruiser diesels start at 130 hp, here is a link to their site.
There are not really any bad ones nowdays - but there will be features that appeal depending on the application and buyer’s preference.
I have used a few over the years, and find the Volvo’s not too shabby. They have their idiosyncrasies and I am a bit underwhelmed with the latest 250hp engine in our local rescue boat, as it has required a rebuild at 2000 hrs and after a further 800 hrs just had turbo replaced, Sump welded due to corrosion and now the compressor seems to be intermittent. This engine is Government property and serviced ridiculously often - it is disappointing. On the other hand my old B165 just keeps powering along with over 5000 hrs and every sign that it will last another 5000. The ‘O’ ring seal design is pox.
The best economy and power so far for me is definitely the Yanmar - yes I own Volvo but the Yanmar is very very good. I would suggest they are potentially the most incredibly economical engine I have used. We spent 3/4 of an hour one night with a new boat trying to put the last 15ltrs in the tank - eventually we realized that a 318hp engine used 24ltrs for 8 hours of commercial fishing - mostly slow speed but even so that is phenomenal on a 30 footer with jet. Should my Volvo go paf I would go Yanmar. These engines are purely designed as a marine engine unlike nearly everything else - service points are for a boat not for a truck so you are not expected to take the oil filter off from underneath and similar stupidity. Perkins are a very well known brand and pretty bullet proof. Chev V8 diesels are frequently marinised, and sound great - some have been good, some not so reliable where I am - they seem a bit of a lottery but are great while going. There are a lot of engines out there - and you will have to make your own mind up.
I have not put links to these as any Google search will provide a million links. There are of course many other brands out there but I only speak for the smaller ones I have spent time with. GM’s are very good but too big for your use - they are very economical until turbocharged - plus who doesn’t love a V8? Cat’s are good, but thirsty. Fiats are o.k. but pretty expensive for bits. Marinising a car, commercial or four wheel drive engine is always an option - but re-sale can be very low as people don’t trust the concept, Some brands do just that - convert a Kubota or similar for marine use - I think Westerbeke does this amongst others - they seem to have a good product.
The engine is separate from the stern drive - it is not really important what the engine is as the gearing of the leg and prop will be set up for whatever power source you choose. I favour jets, Castaldi are a good choice, but that is just my opinion. Stern drives don’t forgive powering on while tilted up too high because of the uni joint, think of them as the lower bit of an outboard - the bellows etc. need constant attention.
I think your power range will be inadequate for a twenty footer if a planing hull, unless very flat hulled. 150hp would be the minimum, I would look more towards 180, even 200hp so the engine can cruise at a more economical revs with plenty in reserve. It is a false economy to under power, just as it is over expensive to over power. It is not a direct comparison with outboard power ratings, as they are lighter in general, but a correctly set up diesel will outlast and out pull most equivalent sized outboards, and gives a low stable feel to the boat due to the location of the engine. Economy over long trips and time is almost always better with the diesel - and you can run them on cooking oil!
Take your time and try and use or get out on some similar setups to what you want to build - that will ultimately answer you questions on size etc. And it will give direct feedback from actual operators.
stay away from Volvo. have twin diesels on my boat and have had so much trouble and expense that i just let it sit. replaced almost entire system. at one point the dealer had to order parts from europe.