[rivrhnd]

I have a 24' Party Barge and wanted to optimize the performance of the Evinrude 115 on it. It is a 1993 motor and the prop got hammered! I don't want to cough up for a Stainless as the Colorado River is just too shallow. Any thoughts on what the best pitch might be for this lumbering barge? It is only a pontoon, not a tritoon.

[Silvertip]

The starting point when looking for a prop is to determine what you have now. The diameter and pitch are normally stamped on the prop barrel or on the end of the hub behind the prop nut. The next step is to tell us what the wide open throttle rpm was with an average load before you damaged that prop. That tells us whether or not the existing prop was right or in the ballpark. Without that data you are starting from scratch and unless someone is running the same exact configuration of boat, engine, load, and altitude, there is no way we can tell you what you need without guessing. The best prop for your boat is one that allows the engine to operate at or near the manufacturers recommended wide open throttle RPM with an average load. And just so you know -- even though you may not run wide open all the time, that doesn't change the fact that if the prop is wrong at WOT it is also wrong regardless what RPM you run. Since we don't have that data, I will make a swag and say a 13-3/4 x 17 prop will get you in the ballpark. Depending on the weight of the boat and altitude (which greatly affects power) you may need to drop to a 15P.

[DMAN1968]

My old 24' toon with a Johnson 115 runs best with a 14 x 13 pitch prop. If you look at the numbers on your old prop that should give you a good starting point to go by. But, like Silvertip said, you want to shoot for the maximum rpms with a average load on the boat. This will get you into the correct rpm range across the entire throttle range.

[rivrhnd]

The portion of the Colorado River I am referring to is in the middle of the AZ desert so it is Sea Level. Pretty sure it was a 14/13 as well but I didn't take the prop off as I had other issue's going on with cooling. I had impellor changed two weeks ago so I think calcium deposits built up or the oil pump is going south. The warning beep kicks in within a couple of minutes of running it over 4k rpms. Staying at 3k it is fine. The boat shop out there is checking into it. The reason I ask about the prop is he wants $150 for the prop and I see a lot of aluminum Solas props for $99. I'm not into paying somone 50% markup over what you can buy these for from just about anywhere. As I said, the boat just plows and probably tops out at about 23-25mph, maybe. Max RPM, I have never paid attention to as I run it at about 4200rpm for cruising. Thanks for the advice...