1957 Johnson 7.5hp AD-11

[swedishsam]

Hey,
Semi-Newbie here recently bought this great little motor from an old timer who rebuilds them. A few concerns I do have is how much water should be pumping from the exhaust, as it gets really hot when running and I barely see any water coming out. Although when I flush the motor when I get home, I hold the hose up to the Water intake and it almost and sometimes kills the motor, but if I put the hose up to the tell-tail/exhaust It runs better and keeps the motor cool to the touch. So I'm a little confused to say the least. For the most part it runs great out on the water after a few adjustments to the High/low settings which are different every time i go out. Yet sometimes It will run really strong for a few mins and then falls off just a bit to where i notice.. Any suggestions or information about how much compression this model should have or is it possible the impeller is installed upside down, I run 87 octane 16:1 oil as according to the condensed service data manual that I have.

Thanks in advance!
Sam

 

[F_R]

Re: 1957 Johnson 7.5hp AD-11

You must check the water pump. And stop sticking the hose up. That is no way to flush it and there is danger of destroying the motor by water getting in the exhaust ports.

There should be a healthy spray out the exhaust relief port on the rear.

Compression should be around 85 psi

 

[swedishsam]

Re: 1957 Johnson 7.5hp AD-11

Thank you FR.
I will check the pump. Could you suggest a better way of flushing the engine of salt water since putting it a barrel does not seem to work. Thanks!

 

[Daviet]

Re: 1957 Johnson 7.5hp AD-11

Why can't you flush it in a barrel, just make sure the water level is well above the water pump.