High RPMs

[2ifbyc]

I just bought my first boat. It needed a new prop but the old one had no numbers or anything on it for me to match. I asked around to find out what the right size would be for my boat.(19ft wellcraft american with a mercruiser 170). I ended up getting a 14x19 aluminum prop. I installed it and the boat is running great. The only problem i noticed is that the tach was reading just over 5000 rpms at WOT. The manual says i should be between 42 and 4600. What should i do or check?

 

[coastalcruiser]

Re: High RPMs

sounds like your motor is ok!
try posting this in the props forum.

 

[Bondo]

Re: High RPMs

Ayuh,.... Try a 21", or maybe a 23"...

 

[cooter2506]

Re: High RPMs

Hook up a tach meter to it to verify your tach. Tach could be wrong. But My uncle has that same boat and he runs a 21 pitch at 4500rpm. But if your tach is correct sounds to me like you need a 23 pitch.