56 johnson 3 hp high RPM ont very good

[scruffy1963]

I have completely went through the 3 HP Johnson, Rebuilt the carb. New wires, new Mag's and Points & cond. Points set at .20. New plugs. Motor starts easy and idles nice runs smooth at wide open but it is not reaching the high peak that my others are. I tried different needle valves same result. Float is set according to specs. Why can't I get High speed out of it.

 

[lindy46]

Re: 56 johnson 3 hp high RPM ont very good

High speed is not very high on a 3hp anyway. How is the compression?

 

[tx1961whaler]

Re: 56 johnson 3 hp high RPM ont very good

....and is it firing on both cylinders? It will run just fine on one cylinder.

 

[scruffy1963]

Re: 56 johnson 3 hp high RPM ont very good

I am going to try the Plug wire test removing one at a time 1st. However when I start others like it they scream at a higher RPM. Compression is 65 each cyl. Thanks

 

[lindy46]

Re: 56 johnson 3 hp high RPM ont very good

Yup, check to make sure she's firing on both cylinders. Compression is a little low but not bad - I'd shoot some seafoam into the cylinders and let it soak overnight, then re-check compression.

 

[JB]

Re: 56 johnson 3 hp high RPM ont very good

Timing?