15hp Mercury 2003 Prop Trouble

[ChrisCKL]

Hi all, i have used my Mercury 15hp for about a year now and I seem to have a minor problem. Occasionally, when i drive at max speed on one of my small/light boats with a heavy person in it (zooming around), my motor revved up and lost its power for a moment. I slowed down and then it was fine when i picked up speed again. I am told that it was because of the quick acceleration that caused alot of stress on the prop. It seems that the propeller is has minor damage on the inside? Anyway, because of this tiny problem, and my wanting to go even mroe faster, i want to buy a new prop. I have read that the more pitch the faster it is? and the smaller the diameter the faster it is? I am wondering if this is correct. my standard prop is a 3 x 9"x9" this means 9" diamter and 9" pitch right? What prop shall i get? I also want faster accel and faster speed. is this too much to ask?<br /><br />My engine is actually a 1997 from the serial number but never used until 2003.

 

[y not]

Re: 15hp Mercury 2003 Prop Trouble

More speed and more accelaration are almost always mutually exclusive. Drop the pitch size to get more accelaration but increase it to get more top end speed (to a point) so now the big question WHICH IS MORE IMPORTANT TO YOU!!! Speed or accelaration you need to decide this and then get a prop to suit that desire.<br /><br />A small amount of prop damage can do funny things, that said, balance your load in the boat and often odd things like cavitation or airation of the prop seem to disappear.

 

[cobra 3.0]

Re: 15hp Mercury 2003 Prop Trouble

You need to see how high your engine is reving at WOT and from there determine if you are propped correctly. You may be over-reving your engine. My 15 has a 9" dia. x 11" pitch on a fairly light aluminum boat. It would probably make you go faster too.<br /><br />Using a tiny tach will help you determine this.