1960 60 hp sea king wont run at 4500 RPMs or higher?

[Dewey]

I have been working with this engine since may and have made great leaps and bounds but since I have installed a tach I have realized that the engine is not running at the right rpms. The model is GG8850A it is a V4. It is supposed to run at 4000-5000 RPM (60hp at 4500). It was only running at 3600-3700 with a 10.25x 10 prop on it. I have switched to a 10x 9.25 prop and now it runs at about 4300. This is on a 1968 Larson Glasspar Avalon 16ft fiber glass. There is also a hydrofoil on the motor if that matters. Is this going to be as high as i can get it or are there some things to check on the motor to see if it will run higher. All four cylinders are firing. If any one has any suggestions I would greatly appreciate them.

 

[Dewey]

Re: 1960 60 hp sea king wont run at 4500 RPMs or higher?

i have tried running it without a prop and it will go above 4500 but that is the only time. any suggestions.

 

[Dewey]

Re: 1960 60 hp sea king wont run at 4500 RPMs or higher?

I have also tried the high speed adjust knobs that has not made a difference for the better. are there anyother things i can do?

 

[Lark40]

Re: 1960 60 hp sea king wont run at 4500 RPMs or higher?

I think that 4300 sounds about right. I seldom have seen old OMC engines go much higher than that on non-racing boats. My Lark 40 tops out at about 4300 rpm on a 250 pound boat regardless of prop pitch.

 

[Dewey]

Re: 1960 60 hp sea king wont run at 4500 RPMs or higher?

thanks for the info. I was not sure if it should be higher or not because the manual said between 4000-5000.