i just got a new evinrude etec 60hp on my 24pontoon. I pitched the motor and got the right sized prop. only problem is, at WOT the prop spins out and the motor revs up. This only happens at WOT combined with hitting a little wake or something. I was thinking maybe a tail fin or something would help. any suggestions? My old motor didn't have this problem and it had a tailfin installed on it.