1988 Yamaha 90 WOT RPM ?

[Shepherds Ride]

I have a 1988 Starcraft 28’ pontoon with a Yamaha 90 hp of the same year. At WOT the tachometer reads about 3500 rpm. That seams a little low to me. How do I check the accuracy of the tach? If it’s correct it look to me that I need to change the props pitch, but the only number on the prop I could find was 14-K. Does amyone have an idea what that 14-k stands for? <br /><br />Thanks

 

[Silvertip]

Re: 1988 Yamaha 90 WOT RPM ?

Probably stands for 14-inch pitch. If you determine the tach is correct, you need to first determine if the engine is running properly and that the throttle is opening fully. If everything checks out, a prop with less pitch is needed (although the 14 should allow higher RPMs than you are seeing on a 90HP engine). 3500 at wide open throttle is definitely lugging the motor and that's not a good thing.

 

[Ray Neudecker]

Re: 1988 Yamaha 90 WOT RPM ?

I would agree with Upinsmoke on everything except the 14 pitch on a 28 ft Starcaft poontoon could easily be too much pitch.