Yamaha Knocking

I have a 2005 Yamaha 150 that

I have a 2005 Yamaha 150 that knocks when in gear at low rpm(about 500). Speeding up to about 600 rpm eliminates it. Unfortunately 500 rpm is about my trolling speed. My dealer says that it's due to my stainless prop. Doesn't make sense to me. Any input? Thanks.

yes it si the prop. the motor

yes it si the prop. the motor over spins the prop when turning it then when it catches back up u hear the clunk.

Had the same problem with my t

Had the same problem with my twin 225 4stokes. You can do some more searching on this issue and find other threads that relate the problem to the slop in the drive shaft if the impeller is not installed properly(we did it ourselves). Our knocking went away and then came back. Our dealer was a complete joke(f Sundance Marine in Fort lauderdale F U!) and Yamaha said not to worry about it but since engines are still under warranty they would not send us anything in writing! Eventually we had the drive shaft bushing replaced but the noise had stopped after the third water pump change and bushing....

"Hey ellis, just came across t

"Hey ellis, just came across this very informative step by step web posting for yamaha water pumps, might want to check it out. http://www.bogueinletnc.com/yamaha/9.html
dont know who put it out there but it is very good."

"maybe get a kicker or trollin

"maybe get a kicker or trolling motor for trolling. my 90C Yamaha knocks and clunks a bit at very low RPM's. these are performance engines,many with a high HP per Cubic inch,so even with the ECU and reed valves, they're probably never going to be as happy at 500RPM as they are at 5000RPM. just my opinion. Good Luck!"

500rpm is a low idle speed i w

500rpm is a low idle speed i would put it back within manufactures specs

"500RPM trolling might increas

"500RPM trolling might increase to 750+RPM's in neutral. maybe add a trolling plate that attaches to the cavitation plate and flips down for trolling, allowing for slower trolling speeds with slightly higher engine RPM's. should be just what you need for your application...Cabela's I believe sells several different models of these bolt on plates."