Re: Wrong Prop??
It seems to me like you might have a couple issues going on. The prop pitch seems pretty low for that size boat, which would explain the high RMP's, but it should come out of the hole OK unless it is way underpowered, you have too much weight in the stern, or the trim is way off.
You can tell if the trim is way off pretty simply if the boat is hard to steer or really pulls to one side or if it seems to lug to get up on plain and then the RMPs shoot up as the bow comes down and/or the bow bounces. A properly trimmed boat should be easy to steer and you should be able to relax on the steering without fear it is going to shoot off one way or the other and should have a bow ride nice and steady.
Assuming you've adjusted the trim as well as you can, the first thing I would do is take out as much weight from the stern that you can and/or move it as far forward as possible and take a few test runs. If this works, you can then see about changing the weight balance permanently. I have a 18' fiberglass center console with duel batteries that were in the stern along with the fuel tank and simply moving the batteries to the bow compartment and the fuel to the center of the boat helped substantially.
If that does not work or if it does but you can't relocate things permanently because of the layout of your boat, a relatively cheap thing to test could be to install a Stingray Hydrofoil, which sells at various stores for about 50-60 bucks. I had a 16' tracker with a 60 HP that had similar issues and the Stingray really worked wonders because I could not easily redistribute the weight. It is easy to install and if it doesn't work, it does not hurt to keep it on.
If neither of those things work to your satisfaction and/or does not addresses otthe high RPM issue, you will likely have to get another prop. With the proper tools (a $12 prop wrench, a pair of small pliers, and a 12" piece of 2X4) you can change out a prop in about 3 minutes and it should be pretty easy to find used props for your motor on ebay or similar. It may take a few tries to get it right, so you may want to go with a prop store or reputable marine shop since they will have more options to work with and you will only end up buying the one you need (but it will cost you a bit more). I would start with a 16 pitch prop, but you may also want to have a 19 or 14 pitch prop on hand to try too. Without a tach/GPS it will be hard to test the results too accurately. I would at least get/borrow a cheap hand held GPS so you can track your speed at WOT to see if there is any improvement between runs.
Good Luck!
