new to me

[gotmeaboat]

took the boat to the shop last night. checked compression and all were right at 110. changed the plugs to the proper plugs. checked spark and all were good. looked at the prop. there was a four blade 14 x 21 on it, we replaced it with another prop we found in the console, it is a three blade 14 3/4 x 17. how bad would the 4 blade make the boat run? 1994 18.5 Hydra Sport w/Johnson 150hp. when i took the boat out last week it would only run 3600 rpms and when i woulg throttle back to 3000 the rpms would just continue to drop while the boat was still moving.
tom

 

[Gary H NC]

Re: new to me

It should turn at least 5500 rpm. The lower pitch prop will help but be sure the motor is in tune first.
3600 rpm sounds like you may have other problems.
I would do a carb rebuild and link and sync to be sure.