My prop is over reving engine.

[Rjbrice15]

Hello I have a 1992 Stingray 18 foot bow rider that I purchased a few months ago it has a 3.0 MerCruiser. When I purchase the boat the prop that was on it is a 15 and a half x 19 pitch stainless prop. I contacted Michigan wheel and they told me that the boat with that motor called for a 14 and a half by 19 pitch but since I was already getting 5200 RPMs out of the prop that I had on it I would need to go with a 14 and a half by 21 pitch. The 14 and a half by 21-pitch prop that I purchased increase my RPMs to 5600. If the boat calls for this prop why am I having problems? The W.O.T on the boat is 4400 - 4800 RPMs

 

[flyingscott]

I would double check your tach sounds like something wrong there.

 

[alldodge]

Your tach is reading correctly

 

[cptbraine40]

My first boat was an 18' bowrider with a Mercruiser 3.0. It has a 21" pitch 3-blade prop on it. Now WOT was right at 4800 but man was it a dog to get on plane, cruiser, etc. I then switch to a 4-blade, 17" pitch prop and wow.............it was a whole new boat. Now I did loose a few miles on the top end but everything else was 1000% better. My WOT stayed right at 4800. In my opinion, get a Solas Rubex 4-blade 17" prop. That should drop your RPM down about 400, putting you right at 4800.

 

[jimmbo]

What gear ratio does your drive have? You should be able to locate it on the MerCruiser label on the outdrive

 

[steelespike]

What is your gps speed at 5200?

 

[Rjbrice15]

Thnaks for the interest in my post and helpful words. Turns out the thrust washer that came in the hub kit was smaller than what was it was suppost to be. Wierd that somthing so small can cause such a ruckus. I used the old thrust washer and now it's running top end right at 4700. I happened to go to the marine store and was talking to a tech there and he informed me to try the old thrust washer. Problem fixed.