Johnson Seahorse 1964 40hp - high-speed problem

[manderson7]

This weekend I started having some trouble with my trusty 1964 johnson seahorse (40hp) I got it fired up just fine however once I would accelerate over 10 mph the engine rpms would continue to increase but prop would stop turning. This problem has persisted ever since. After I got the boat back to dock to play with it I started having trouble starting it - once the starter pinion gear drops of the flywheel the engine dies leaving an electric whine.

In the past week I had a log jam between my propeller blades and the lower unit while docked and I tried to reverse out before discovering the jam causing the blades to dig into he wood. Other than that everything has been working great.

I'm guessing there is something wrong with the fuel intake - but i'm not a motor head. Any thoughts or suggestions would be great.

Thanks,
Michael

 

[Joe Reeves]

Re: Johnson Seahorse 1964 40hp - high-speed problem

First... try another prop as the hub is most likely slipping. If so, you can get your original prop rehubed.

If your engine has electric shift and the prop isn't the problem, then you have lower unit problems.

 

[F_R]

Re: Johnson Seahorse 1964 40hp - high-speed problem

Don't know what the starter has to do with anything, but the slippage is what Joe said. Most likely a spun prop hub. Or a $$$lower unit problem IF it is Electramatic Shift.

Prop hub is simple to test. Make a mark on the plastic prop nut, and another mark on the propeller, aligned with the first one. Run the motor till suspected slippage occurs, then stop motor and look at the prop. Are the lines still aligned? If not, the hub slipped.

I haven't checked lately, but I believe iboats has replacement props.