This repower was done on a 28' Carver. You might want to go with the next step up engines, however take a look at the performance numbers and economy and all you will say is WOW!
I have also included a forum link on this repower at my other haunt over at boatered which includes photos.
Hope this helps.
RWS
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Repowering Your Boat - Bob Benton
I repowered with Yanmar diesels replacing the stock Mercruiser MIE230’s. I used twin Yanmar 4JH4-THE engines along with the existing Borg-Warner Velvet Drive trannys (1 to 1) and Walker V drives (2 to 1). The engines are rated at a continuous 110 HP each at 3200 RPM. The engines are not yet fully broken in so I haven’t been able to do a complete performance sheet but so far it averages 24 MPH at WOT and 18 MPH at 2800 RPM cruise. Mileage I don’t yet know since I don’t have a flo-scan.
So far, I am thrilled with the repower. I love to cruise to the Bahamas and putt around in the small remote islands in The Bimini’s, Berry’s and Exuma’s. Before I was always limited by range with the gas engines. That will not be a problem any longer.
With the repower I lost 5 MPH WOT speed and 4 MPH cruise speed. But, from the preliminary numbers I am seeing, my mileage more than doubles at WOT and almost triples at cruise. Then, if running at 7.5 KTS, which is my usual putt along speed, the mileage is absolutely amazing.
My total expenditures were around $45 G’s but that includes a few extra things and upgrades I had done at the same time: completely rebuilt both trannys and one V drive, bought one new V drive because of counter rotation, all new halon system, bottom paint, redo waterline pin stripes, etal.
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here's the link to the forum discussion with pix
http://www.boatsafe.org/forum/topic.asp?TOPIC_ID=134786