Not hard to swap the prop back to try that out:
Remove the Cotter pin, use a piece of 2x4 to block the prop, undo the prop nut, taking care to note what order stuff comes off in so it goes on correctly. Change prop, making sure to get the thrust washer on correctly first; replace all te mounting stuff, torque as appropriate, and replace cotter pin.
Sounds involved, but shouldn't take more than about 5 minutes assuming you run into trouble. About 3 minutes if you don't.
You really should run it at WOT to check whether you're propped correctly or not. Eventually, you're going to hit flat water and want to open the thing up.
It sounded as if you didn't have a tachometer on the boat? If not, I'd suggest getting one, even if it's just for diagnostic purposes. Tiny Tach makes a little clip on jobbie that sits under the cowling (though I'm not sure how easy it would be to run the boat and check that thing...)
Anyway, hope all runs well from here.