So if you have your motor rebuilt, and the "reason" they put oversize pistons in it is to get rid of scarred cylinder walls, and not to increase hp....you're ok?

Not something I want to have to answer during a polygraph, or a protest I want to defend against.

Isn't it against the law as well?

Make sure it isn't just a different cowling.

That makes it tricky buying used boats that have had the power head rebuilt...you don't know if they put oversize pistons in or not.

It's not against any law to overpower but would look bad in court if you were involved in an liability suite

As far as rebuilding a motor, oversized pistons, performance reeds, etc., rules pertaining to this are written regarding the factory rated power of the engine. Don't over think this. No organization, club or tourney trail is going to dyno test your engine.

Put 150hp letters on it instead of 175?? Works

There are plenty of boats out there running with a cowl that says less HP than it really has. Its a dumb thing to do tho.

Never quit figured out why it is a big deal to put a 300hp motor on a 21' boat, yet I can go buy a Kawasaki personal watercraft that is less than 12' with a 310hp engine and be legal.

I have seen a number of boats over 20' that had "unlimited horsepower" on the rating plate. I am not sure how an insurance company would handle that.

Not arguing, but the only one I know of with the 250 limit is BASS. My dad runs a skeeter with a 300 and is ok to fish every other trail I know of.

Back in the late 70s I had a boat rated for an 85 but I had a 135 on it with an 85 cowling. Everything worked good until I went to a tournament that they were checking things real close as luck would have it I was checked before I had entered. Guy doing the checking said I was over powered told him the motor said 85 he pointed to the serial number and said see first 3 numbers there 135 it is 135 hp. didn't bother to enter the tournament.

Used to have a buddy that ran a 140 Mariner but had a 115 cowling. He loved to race other 115s.

My brother in law had an old Skeeter Hawk that was rated for 30 horses. He stuck a Johnson 50 on it.
Man would that thing power slide.

I'm no expert but jet drive and prop spin are two very different animals. I've been in a boat with a 300, rated for 225. It almost turns over sideways when you gun it, just from the prop torque.

I know a guy who lives really, really close to me with a 18.4 ft. champion and has a 200hp merc on it. Its rated for a 150hp. Insurance wasn't a problem!!