Prop questions from newbie

Hi all and thanks in advance for any help. I have a 24' raven pontoon with a 1989 75 hp mercury 2 stroke 3 cylinder with cavitation/ventilation problems. I do not have much history on this boat as I am restoring. At present it has an 11 pitch prop(48 77338 a40 14") The motor runs fine and with 2 people on board it tacks to approx 5800rpm. There is a on and off prop slippage throught acceleration. The slower the acceleration the less prop slip. Hard right hand turns are a sure way to get the slippage. I do not have a speedo but I am not real concerned with speed. With the motor trimmed all the way down give best results but boat bow seems to plow. With positive trim to raise the bow more slippage is produced. I marked the hub and prop and went o wot. the marks were perfectly in line upon return. The motor does have 1 more hole that I can lower on the transom. Where do I starts? Thanks in advance for your help.

Re: Prop questions from newbie

I would lower it that one more hole.Is the prop in excellent condition?
If the prop has a worn look a new prop may solve the problem.
Also a 4 blade would help.
If the prop number ends in 14 that usually means its a 14" pitch.
How ever It could be 14 X 11 Diameter X pitch. and 11 makes sense.



5800 Is a little high the motor is rsayted at 5250 5500 might be ok but 5800 is stretching things.

Re: Prop questions from newbie

It sounds like your prop is actually slipping on it's hub whereas the rubber may be worn out. My advice is to get another prop and make your current prop your emergency prop. Always have an emergency prop on board. Here is a link to the Mercury propeller selector:

http://www.mercurymarine.com/propellers/prop-selector/#

Yours may come in around a 13.75 x 15 or a 13.25 x 16. Tell us your results.