"Jens_Erik" wrote in message
ups.com...
I just bought a used Bayliner Trophy 23 foot and the engine is OMC 5.7
1989 (model 574 APRMED), i believe it has 250 HP. The prop is 15'' x
17''. But the max rpm I get is 3400. Is that the maximum rpm on this
type OMC engine? I should think it lacks at least 1000 more rpm. I
believe the engine should be able to get at least 4400 rpm at WOT. The
max speed i currently get is just 24 knots. The engine seems fine and
I just replaced the spark plugs. Anyone has ideas of what could be
wrong?
Thanks
Jens-Erik
Nuuk, Greenland
My boat: http://www.123hjemmeside.dk/Nukappiaaluk/1442331


It's hard to tell, not knowing what the original prop was, how much that
boat weighs, (is it waterlogged?) or how you have it loaded.

Assuming there are no problems with the engine, coil, carb, etc., it is
possible that the previous owner installed a higher pitch prop, thinking it
would go faster (common mistake). FWIW, one of my first boats, a 1982
Century with a 5.7 L engine and alpha drive had a similar prop (17 pitch)
when I first bought it used and the engine would only get to about the same
RPM (3200-3400). I had to drop to a 12 pitch prop to get the RPMs up to
over 4200.

RCE