PROP SELECTION HELP

[Wonbigfish]

I recently had to replace my 90 hp force. I found a 1997 90 hp with great compression. Mounted it up on a 16 1/2 Palm Beach. Swapped out carbs, new water impeller and ran great. The prop seemed perfect and it was for a year. Decided to replace the aluminum prop with stainless of equal performance. Couldn't get prop off lower unit to find size numbers. Had to cut, beat & cuss it off. Only to find nimbers missing or corroded away. I read several web site sizing sugestions and purchased a used Ballistic 13 1/2 x 17 stainless prop. It just doesn,t have the same hole shot nor speed. I don't have a tach but I think it's running at higher RPMs. I fish the flats of Mosquito Lagoon. It requires a quick jump on plane & enough speed to do the skippy through flats. I am considering a 4 blade 13 x 19 Aluminum or Stainless.
Any comments or suggestions appreciated
Wonbigfish

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[Frank Acampora]

13 X 17 should be about correct for that hull and engine combination, However, my experience with Ballistic is that because of the blade area and the full cup, it runs at a slower RPM than a stock type prop and also gives a slightly slower hole shot. For example, I was running a 125 on a 14 foot hull and a 21 pitch cleaver ran 5900 RPM. A 21 pitch Ballistic ran 4500 rpm but top speed remained the same.

However, without a tachometer you are flying blind and any prop change or modification you make is simply going to be a guess. At the minimum, before you do anything else buy a tiny tach so you can at least have some idea of RPM you are actually turning

If you intend to sell the Ballistic, then make no modifications. If you intend to keep it then try venting the hub to unload the engine at hole shot and thereby decrease the time to plane.