Re: Horsepower Rating
Pretty certain 1980 was rated at the crank. But the difference is minimal for practical purposes. Proper mainenance, setup, and prop, can have an under powered motor running better than an improperly set up motor with greater hp.<br /><br />Variance to current prop rating is between 3 and 10%, depending on who you want to believe, and the number of mechanical obstructions between the crank and the prop.<br /><br />The bigger factor would be manufacturing variances. NMMA outboard ratings have a "slop" factor of 10%. Meaning that a 50hp motor should fall into the 45hp-55hp range. Some motors actually put out more than the rules allowed, which was another reason for the move to standardize hp ratings.<br /><br />So when your motor was new, it may have put out as little as 68 hp, or as much as 90hp. It was likely in the 75-80 hp range.<br /><br />Not really worth worrying about.<br />As long as it gets you out there and back home again.
