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wongaga said..
I like your style in trying to adopt a far cheaper alternative solution, but using 25hp in a little boat might lead to some difficulties in prop selection, and in keeping the engine adequately loaded. Is it possible to get something closer to the 15hp?
I also share your reserve re buying a s/h direct replacement, but you could spend a bit on having it fully checked out: a compression check and oil test will tell you a lot about the innards. Installation would cost next to nothing, and you would have spares from your old engine, and a heap of unspent money left to cover any later hassles. Don't underestimate the cost (if not diy) or the incredible hassle (if diy) of redoing the engine beds.
Cheers, Graeme
when I was looking at that listing it states that the engine develops 15 HP at 2300-2500 rpm range, which I guess is the optimal rev range for this engine. I do not think the prop size matters, since the engine rev is rated at max 3000 rpms (at which the 25 HP is gained) roughly the same performance from the Yanmar. I think the prop size would matter if the rpm range would be considerably different. As I was told, the torque gets you going and the hp keeps you going. Yes, probably the 25 hp is a bit overkill for a 29-30 foot boat, but hey, I would have at least the confidence to fight any current. But this would also mean that I would be able to use an alternator at higher rating too.
I am handy and do not mind a challenge, I recon as long as I get my measurements right, I could fabricate the mounting brackets fairly easily. There is enough room around the engine to be creative if needed be. The most problem I would probably have is matching the tranny to the engine (was thinking of reusing the old yanmar's and leave everything else alone). This would still be an issue if I decided to install a dedicated marine diesel.
still would be good to get more info about the quality of these engines ( I know, $2500 what do you expect). If they lasted only half of what most yanmars are capable (10000 + hours) I recon, it still would be a better option than a gamble on a second hand option at a similar price.