Prop help recommendations needed

[Roc0302]

I have recently bought a 1985 Johonson 70HP outboard for our 20' pontoon (rated for 90HP). I am unsure as to what pitch to be looking for. We would like more cruising speed as opposed to hole speed. I have tried to study up on this, but do not know what the max RPM's are for our motor. I believe that a 13 or 15 pitch are my best choices, but I'd be more comfortable hearing from experienced people. Thanks!

 

[QC]

Re: Prop help recommendations needed

Your WOT RPM is 5000 - 6000. How fast does she spin now? What pitch? Take a read of the "Read this first" stickie above. What our experience will tell you is that you must have Wide Open Throttle RPM to make any choices on propellers. The stickie should help you.

Oh, and welcome aboard!!!

 

[Roc0302]

Re: Prop help recommendations needed

I do not know what the RPM's are now (nor do I know how to find out). The prop on it now has 19" pitch, but motor was on a bass boat before. As far as I know/able, I have given all info that I am able to.

And, thanks for the "welcome"!