Re: Just curious, how are/were motors rated?

[wiscoboater]

Back in the 50’s and 60’s Mercury under rated the HP output of most of their motors. Kind of Carl’s way of "cheating" the system in the racing circuits. Outboards were rated at the powerhead until sometime in the early 80’s I believe but dont remember what year that changed to rated at the prop shaft. About a 10% to 15% difference in rated HP when measured at the shaft. If you want a real view as to what was going on in the outboard world read the book Iron Fist. It’s a real eye opener to how competitive the market was and the lengths one mans company went to to game the system.