New prop, lower RPM's

[DumbBass]

'89 Johnson 60HP/ 17' Key West DC. Just replaced the old aluminum prop with a new stainless of the same size/pitch (13 3/4 x 15P). After resolving an overheat issue, I ran the boat yesterday and have a WOT RPM of only 5050 with 1 person, 1/2 tank of gas and trimmed out as far as possible. I was able to run 5500-5550 RPM with the old aluminum prop. The boat runs fine, jumps on plane and actually sounds better. I acn now stay on plane at less than 3000 RPM when before it wouldn't plane at less than 3700 RPM. Is this an issue? Can a stainless prop be "tweeked" to reduce the pitch a bit to increase RPM's?

 

[CATransplant]

Re: New prop, lower RPM's

Actually, that stainless prop bites a bit harder in the water than the aluminum one. Because of that, you may be able to compensate raising the outboard a hole on the boat.<br /><br />You'll probably see a trim and setup expert along here shortly on your question. If Dhadley shows up, listen to his advice. He's the best there is here on this topic.<br /><br />Even if you do nothing, though, it sounds like you're getting better performance. You'll want to tweak it, but you can go enjoy your boat anyhow until you do.

 

[walleyehed]

Re: New prop, lower RPM's

You'll need to get that RPM back up to the 5500+ mark.<br />As Cat says, start by raising the engine 1 hole at a time and test. Keep going up until it wants to ventilate too easily.<br />I think you're going to end-up in the 3rd set of holes from the top, depending on the brand SS prop you have..