Thanks for the responses however I needs some additional suggestions. I have 2 props, the original that came with the boat has the old style metal hub/dampner and the new one has the plastic hub/dapner. When I changed from the old to the new I noticed that the prop did not fit as tight (had in & out movement after tightening) as the old one. I noticed at low speed (going down a canal) that it made a hum almost whistle sound. I took the prop back and they gave me another one but said this is common with the new Mercury design. After about 10 hours of use my problem began where the motor would over rev once it was just about planed off. The motor is fully trimmed down. I tried putting the old prop back on but the problem did not go away so I think I can rule out the prop.
Thanks in advance for helping me diagnose this problem.
