top end speed

[mandydoggy]

I have a 1975 Grew245 with an 235hp omc, when at WOT the rpm is 4500 but the speed is only about 20mph, the prop is a 14x16. Should I switch to a larger pitch prop for better speed?
Thanks.

 

[steelespike]

Re: top end speed

Is your speed by gps?I have a feeling your tach is wrong. I think 4500 should produce about 30 -35 with a 16" prop.

 

[Robbabob]

Re: top end speed

Hey there and welcome to iBoats!

Check out this link http://forums.iboats.com/showthread.php?t=287818 and provide the much needed information.

I'm with Steelespike. Something isn't quite right. Are you sure your current prop is not damaged? Is the engine running smooth and producing performance?

We look forward to helping!

 

[mandydoggy]

Re: top end speed

Hi! and thanks for the reply. the prop is ok, it's a 14x16. The engine is a omc 235hp (Ford 302V8) at wot the rpm is around 4500, the tach is new, and the engine is running smooth. I have had three other of these same boats and I have gotten 35-45 mph at wot with them.
Look forward to hearing from you.

 

[steelespike]

Re: top end speed

Were you running a 16" prop with the other boats?
Same motor same rpm?Bottom clean and smooth?