1991 Johnson 40 VRO Prop question

[tiller7104]

Question......... I waffled a rock on the river the other day and my prop to say the least has seen better days, my boat is running a 13 pitch now...I want to get more top end..do I go higher in numbers (pitch) say to a 17 or down 10 or 12? It is running 3900 at WOT with a 13 on it now, I know that is too low but I am not sure the prop is all my troubles in the rpm department but I want to get the right prop on it and then adjust from there. As always thanks in advance!!! Stuart

 

[angus63]

Re: 1991 Johnson 40 VRO Prop question

Optimize what you have now and then you may need to reprop. Lower pitch equals higher WOT rpm, appx 200 rpm increase for every inch you drop in pitch. Fix what is causing low rpm first. A new prop will only be a bandaid which could lead to something fatal.<br />Good luck.

 

[tiller7104]

Re: 1991 Johnson 40 VRO Prop question

I agree...you just changed my way of thinking 180 degrees LOL. after i wrote the post I thought the very same thing. I know that low rpm or "half speed" can be classic of a running on 1 cylinder senario. I guess it is time to dig into the electronics? Hey angus are you farmiliar with this motor?