Prop Changing help...

[SmoothSL]

Hi everyone, need a little help.. My current prop is running good.. It's on a '96 Force 120 mounted to a Maxum 17'... It's running (water speed) of 48 MPH at 5100 RPM with a prop that has a good deal of damage.. Max RPM for the 120 is stated at 5250.. It is the origional prop.. The size of the prop is 12.75 X 21P.. Now here is my question.. Michigan Wheel has a direct replacement only it is cupped (it's 12.75 X 21P) and Turning Point has their setup, which I think looks great with the interchangable hub, but their props are 13.25 in dia.. Have pitches from 17 to 21.. What do you think??? What big of difference will there be with the extra .5 in dia??? From what I've read, I'll need a new thrust washer for the Michigan Wheel.. Can't find this info for the turning point prop.. Thanks SO much!!!

 

[Bob_VT]

Re: Prop Changing help...

Measure the distance from the prop shaft to the motor and divide by 2. That will establish the diameter. A larger diameter prop of the same pitch will turn slower. So if you replace with a larger diameter I would suspect you will experiance a rpm drop (slight 150 rpms). If you have the room the extra 1/2" will actually only be 1/4" more in diameter.<br /><br />Save to old prop as a backup and maybe spend the $50-75 to have it rebuilt.<br /><br />You will probably attain the same speed with a new clean prop without dings and dents. Stainless steel is great but you might consider dropping the pitch and 1" if you go stainless because they tend to be more efficient.<br /><br />Bob

 

[Spidybot]

Re: Prop Changing help...

If you really want to know.. look here