as they are usually poorly marinized car engines... Yanmar now markets a 250/300 HP diesel coupled to a large Mercruiser leg, which may be a good alternative... In 2-strokes, I prefer Yamaha and 4-strokes, either Yamaha or Honda... That's probably what you need: 3.35 liters for 225 HP at 5,500 RPM, should give you a very long lasting and reliable motor...
BTW, I sailed on a 52' catamaran from the Isle of Man that only had one 9 HP Yamaha outboard for auxillary power: the boat made about 5 or 6 knots under power, which was rather amazing...
Matt,,Me,I have never been an outboard man,If I can't work on it , I don't own it,,,And as far as sterndrives,,,,Volvo-Penta is the only choice,,,,,,Easy to work on , and pretty much bullet proof,,,,,,Their cone clutch shifting can't be beat,IMHO
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