what year was prop vs. crank HP ratings change?

[gregpro50]

OK, I've gotten mixed responses on this question. Some say 82, others 84, and others 85.

I'm mostly concerned about the information with the Mercury I6 motors. I had a powerhead go bad on my '86 115. I swapped an '81 115 powerhead on it which runs great but doesnt have the power of the old motor because, as I have learned it is rated differently. What I am trying to find is a powerhead to rebuild to reinstall that has the newer ratings. My marina has what I have determined to be an '83 and an '84 by the serial numbers that they will basically give me but I just want to make sure that I am not getting one that was rated the old way.

 

[TOHATSU GURU]

Re: what year was prop vs. crank HP ratings change?

The legal requirement went into effect in 1988.

 

[gregpro50]

Re: what year was prop vs. crank HP ratings change?

OK now I am further confused...

 

[tashasdaddy]

Re: what year was prop vs. crank HP ratings change?

1988 was when it went into effect, even though Force never followed the rule.

1988 and above are prop rated.

 

[wbeaton]

Re: what year was prop vs. crank HP ratings change?

That's not to say that there were not prop rated motors before 1988.

 

[gregpro50]

Re: what year was prop vs. crank HP ratings change?

Thats what I am trying to figure out. At least for these Mercury motors anyway.

 

[TOHATSU GURU]

Re: what year was prop vs. crank HP ratings change?

The stated reason for the regulation was to give consumers a legitimate means of comparing engine sizes from brand to brand. The Japanese were becoming a factor in the U.S. and they were all PS rated. As that is the last point in the mechanical aspect of the engine it made since to make that the standard. I may be wrong, but as I remember it there was no requirement of any kind up until the 88 regulation so manufacturers could say engine X was a Y hp without any legal liability. It was probably the last time any Federal regulation regarding outboards has done any good.

 

[jimmbo]

Re: what year was prop vs. crank HP ratings change?

Merc prop rated the 6 cylinder engines, inlines and v6s, starting in 1982

 

[gregpro50]

Re: what year was prop vs. crank HP ratings change?

Merc prop rated the 6 cylinder engines, inlines and v6s, starting in 1982

THANK YOU !!! Thats the exact info I need.

 

[jedimaster]

Re: what year was prop vs. crank HP ratings change?

So what would have more power? For example a Prop Rated 70hp rated motor or a crank rated 70hp motor?

I thought that prop rated motors were faster. Also the legislation came in to make everything prop rated right?

 

[jimmbo]

Re: what year was prop vs. crank HP ratings change?

the prop rated one