Max RPM on johnson 70?

[dirtriderdave]

I have 1974 johnson 70 and was wondering if anyone knew what max RPM on this motor is? Thanks!

 

[DJ]

Re: Max RPM on johnson 70?

"Recommended" is 4500 to 5500. Time has told, that they live a lot longer if they are propped to turn at least 5500 with a light load.

That engine does NOT like to lug. It needs rpm's.

Shoot for 5500-light load.

 

[w sajpel]

Re: Max RPM on johnson 70?

i had a 1979 70hp johnson it ran about 4000 to 5000 rpm but i was told you can change the pitch on the prop you can get more out of it.
on the other hand if you turn too many rs you also can brun it up.