Re: Prop ??????
Your engine can run a 12-1/4 diameter prop and there are about a zillion of them that do. 12-1/4 x 15P was a fairly standard prop for that engine on 15 and 16 foot boats. Diameter will not change rpm much. Pitch is what affects rpm the most. If you are running a 11-3/4 x 17P now, a 12 x 17P will very likely not be noticeable. My question to you is why are you changing props if you have no idea what the WOT throttle RPM is for the engine (it's 4500 - 5500 by the way) or what the engine actually turns at that WOT. If you have no idea what the RPMs actually are or what speed you are running you should not be spending money on props. If the engine is not capable of reaching 5500 rpm, you need to decrease pitch. If the engine revs above that range, you need to increase pitch. And before doing that, check the engine mounting height to make sure the AV plate is at least even with or an inch or so above the keel. Then make sure the engine is properly tuned and performing as it should. Now you can spend money on props -- if necessary.
