Prop help??

[John Hawkins]

Can anybody help me with a prop problem? I have a 79 Mercury, 90hp on 74 terry tri hull. The prop is in really bad shape. I don't know the size on motor right now, But I do know that I am doing about 38mph at 4500 rpm's, so that tells me that the prop on there is to big, need smaller pich, the onlt thing is, I don't know what size to get. Help needed.

 

[JB]

Re: Prop help??

Howdy, Hawk.<br /><br />You can do two things.<br /><br />Measure the distance along the propshaft from the leading edge to the trailing edge of one blade. Then multiply by the number of blades, usually three.<br /><br />Most props have the diameter and pitch stamped on the back hub.<br /><br />My guess is that the beat-up condition of your prop is causing a lot of your loss of top rpm. Get it reconditioned for around $75 and try it out before you buy a different prop.<br /><br />If you are still overpropped, drop the pitch about 1" for each 200rpm you want to pick up.<br /><br />Your Merc ought to be turning about 5500rpm WOT with a light load.<br /><br />Good luck.

 

[John Hawkins]

Re: Prop help??

THANKS, i WAS DOING THAT BEFORE THE PROP WAS DINGED, AND FINALLY A PIECE THE SIZE OF A QUARTER BROKE OFF ON ONE OF THE PROPS, SO WHAT SHOULD i DO?? There is no size on hub. Help needed

 

[JB]

Re: Prop help??

Pull it off and take it to a prop shop. If they can't fix it (they probably can) they can duplicate it.<br /><br />Good luck.