Johnson 9.5hp WOT issues...Ideas???

[CaptainHook]

Got a 1965 9.5hp Johnson. Just tuned up, set the carb up, new impeller, etc...

Starts 1st pull, runs excellent...........As long as the motor lid is off. With the hood on it absolutely will not run right. WOT it won't even get the boat moving!!!

Not getting enough air I guess??? What could cause this?

 

[ezeke]

Re: Johnson 9.5hp WOT issues...Ideas???

You are getting enough air, but it is polluted by exhaust. There are several places that can allow exhaust to enter the engine compartment, which include: 1. the exhaust relief at the back of the engine; 2. the exhaust housing seal; 3. the shift rod boot ; and 4. the impeller housing seal at the top of the waterpump housing.

 

[CaptainHook]

Re: Johnson 9.5hp WOT issues...Ideas???

Yeah, I bet your 100% correct. I guess I just have to eliminate 1 at a time to figure where the issue is.

 

[Rick.]

Re: Johnson 9.5hp WOT issues...Ideas???

Are you running it on your boat or in a barrel? Best of luck. Rick.

 

[CaptainHook]

Re: Johnson 9.5hp WOT issues...Ideas???

Both, tuned it up, rebuilt the carb, new impeller, and thermostat. Runs great in the test tank.

Runs great on the boat too, just has to have the hood off or it falls on it's face!!!!

 

[Rick.]

Re: Johnson 9.5hp WOT issues...Ideas???

Well then Ezeke has given you the right places to look. He knows these 9.5's inside out. Rick.