Max RPM for Johnson 150?

[mbutcher]

I have a Johnson 150, about '79 or '80 model (anyhow, pre-VRO) on an 18' fibreglass runabout planing hull. The boat and motor combination weighs about 950 kilograms (2,200 lbs?). Motor runs well but I don't know how far I can rev it safely. Had it to 4,500 with plenty left. Any drama at higher revs? Any input appreciated.

 

[Dhadley]

Re: Max RPM for Johnson 150?

Set it up to turn 5800 with an average load. At less than that you start to run into premature wear and failure. The motor will safely turn higher than that but the steel (stock) reeds start to flutter at somewhere around 6300. I dont like to turn the (stock) cast pistons over 6700.<br /><br />Good luck!

 

[mbutcher]

Re: Max RPM for Johnson 150?

That is fantastic to know and especially to get an answer so quickly! THANK YOU.

 

[Dhadley]

Re: Max RPM for Johnson 150?

Youre welcome. Keep us posted!<br /><br />Good luck!