HP Ratings

[WEH]

Still gathering info in my quest for a 6 to 15 HP outboard.<br /><br />From reading some of the posts I gather that sometime in the past the outboard manufacturers changed the way they rate the various motors in HP. What was the change and when did it occur?<br /><br />Also, does this mean that a 6 HP outboard with the "newer" HP rating would outperform a 6 HP outboard with the "old" HP rating? . . . or the other way around?<br /><br />Thanks again,

 

[rickdb1boat]

Re: HP Ratings

crappie<br />Believe it was around 1980-82 that they started rating them at the prop. Meaning if you have a 1977 10 HP, it is really about 6 or 7 HP at the prop, as rated by todays standards. And yes, a newer 10 HP would outperform a pre 1980 model.

 

[DJ]

Re: HP Ratings

crappie cruncher,<br /><br />Rick is right. It was about 1980-83.<br /><br />Outboards are now, and since then, rated at the prop. with a 10% leeway + or -.<br /><br />Typical loss from powerhead to prop. is about 10%.

 

[alcan]

Re: HP Ratings

Hello Crappie<br /> So what dose all this rating stuff really mean to us used motor buyers? Not a darn thing. Dollars per horse power is the same probably more than it ever was. (allowing for inflation) Bottom line (unless your going racing) a 10hp is a 10hp. They will all perform about the same job. Condition and price are whats important. All that rating jazz just makes for something to brag about when they don't catch any fish.

 

[slow_boat]

Re: HP Ratings

My '57/58 10hp Johnson will get my boat on plane quickly but my '69 9.5hp Johnson can't get it up at all. They both have the about the same compression, equally balanced between cylinders, and clean carbs, etc. Both run great but the '57/58 is the stronger of the 2. It does turn a bigger prop through bigger gears which might make the difference?