New to props pitch option question

[renaldoaoa]

Due to hub slippage on my 72 25hp Evinrude 10 pitch prop I'm in the market for a new one.

My service manual shows my prop is a 3 blade 9'' dia. X 10'' pitch, but I have the option to use a 9'' pitch.
Since its in the manual I would think it shouldnt matter either way I go.

If I were to go with the 9'' pitch I would have a faster topend and takeoff, right?

If so what kinda speed difference should I be looking at gaining?

Looking around here for props I've found..
Michigan Match Aluminum Replacement Prop
http://forums.iboats.com/bbBoard.cg...26464&cart_id=910518308&engine_id=30&pf_new=1

Would this type be my best option?

Thanks for the help!!

 

[Silvertip]

Re: New to props pitch option question

What the prop "actually is" and what the manual tells you may not agree. Check the prop -- it should be stamped with the diameter and pitch. 9-inch pitch will provide better hole shot. It will probably not increase speed and in fact can cause the engine to over rev although with just a 1-inch change that is unlikely. 10-inch pitch has the opposite effect. It increases speed and decreases hole shot. Pitch refers to the theoretical distance the prop moves through the water with each revolution (ignoring slippage since it operates in a liquid). Unless you know what wide open throttle rpm with normal load you don't know what you need. If you were happy with the boat before, stay with the 10P. If it was a slug getting on plane, the 9P will help. Look at a prop like the transmission in your car. High gear = high pitch = high speed.. Low gear = low pitch = slower speed but better hole shot.