1978 70 johnson max rpm

[mckeemarc]

I recently put a '78 Johnson 70 on my 16' McKee. The motor is spotless, with hardly any hours on it. Does anyone know what the max RPMs should be. I am currently getting 5000 with the ss prop that came with it. (I'm not sure what the pitch is.) The boat is a little slow to get up on plane. I realize that I may be a little short of HP, but the boat goes pretty good once I get it up on plane. I am looking to get this prop re-worked, but don't know which way to go as far as the pitch is concerned. Thanks.

 

[jtexas]

Re: 1978 70 johnson max rpm

model 70EL-78 max WOT RPM = 5000
check this out:

 

[mckeemarc]

Re: 1978 70 johnson max rpm

Thanks for the info jtexas, I think I'll try that.

mckeemarc

 

[jtexas]

Re: 1978 70 johnson max rpm

the "rest of the story"....

 

[mckeemarc]

Re: 1978 70 johnson max rpm

I ran it this weekend and it jumped right up on plane.

Thanks again jtexas.