Need Help with Prop size

[amckee6119]

Hi everyone! I am new here and looking for some help. I bought a 1989 Invader with a mercruiser alpha 1 gen 1 3.0L 135HP engine. The prop is wrecked and I can't get the number off to order a new one. We do a lot of tubing and are looking for more acceleration speed, not so worried about top end speed. Any help or advice would be greatly appreciated!

 

[harringtondav]

Start with a web search for boat propeller. Anyone selling these has a propeller sizing application. I just tried the one here at iBoats, but it's not cooperating. Michigan wheel has one that works. It will give you the correct dia. and pitch. Then shop for any Alpha I prop. this size, and pay the price that suits you.

Also, using a lower pitch prop. will improve your hole shot, but it could over speed your engine at WOT. 4800 rpm max. is the limit. If your boat is a little poochy with the prop that gives you this rpm, you can pitch down, but you need to watch your tach. when you're cruising, and keep the engine speed under limit.

 

[jimmbo]

If the prop is a mercury prop the part # should be on the tube between two of the blade roots.