Tate,
I had tried to modfied a 2003 25hp merc to gain more power but failed. It didn't last long as I thought it should be. Too much money and problems with this motor.
If I were you, I'll look for nissan or tohatsu 25hp 2 stroke and change the gasket gain to 30hp. Or look for 40hp tiller
WS, where do you find those gaskets that bump motor hp up 20%????
Reminds me of Big Daddy Don Garlits telling a story about back in the day when he dominated drag racing. Everyone was trying to figure out his secret.
They used to store all their parts/spare motors in the back of their cars (this is old days here folks!) and one day he was working on the motor and it started to rain. He hustled all his parts back to the trunk, dropping his head gaskets in a puddle on the way and figured he'd get them later. After the rain, he went out and picked up his head gaskets out of the puddle and finished rebuilding his motor.
Next round, he sees all his competition soaking their head gaskets in puddles. They figured that was his secret....
-T