horsepower rating at the prop for what year?

[FireAm94]

Does anyone know what year Mercury started rating horsepower at the prop instead at the powerhead?<br /><br />Thanx<br />Joe

 

[walleyehed]

Re: horsepower rating at the prop for what year?

1985 with some...others came out complete in 1986.

 

[jimmbo]

Re: horsepower rating at the prop for what year?

Merc started prop rating the inlines 6s and V6s in about 1982

 

[phatmanmike]

Re: horsepower rating at the prop for what year?

officially, ALL outboards had to do it at the prop by 1986!

 

[Qld_Kev]

Re: horsepower rating at the prop for what year?

Does anyone know the conversion between hp at the head against hp at the prop?<br /><br />eg I have 55hp at the head, what would that be at the prop

 

[Clams Canino]

Re: horsepower rating at the prop for what year?

I use 10-15% as a general rule (12.5%). The loss is a factor of the right angle turn in the lower unit.<br /><br />-W

 

[Qld_Kev]

Re: horsepower rating at the prop for what year?

So 55 = 48hp, thanks for the help.

 

[walleyehed]

Re: horsepower rating at the prop for what year?

The lower HP engines weren't quite as far off...Big 308 may not be far off, but I'd say 50-52 in my opinion. Depends on the year model.

 

[FireAm94]

Re: horsepower rating at the prop for what year?

Thanx guys!<br /><br />Joe