Horsepower ratings

[MBJJ2369]

I have read in a few posts talking about horsepower ratings being measured at the crankshaft and the prop. It seems as if some manufactures measured differently at one time or another. The posts I have read have created some confusion in my brain (which aint hard to do) and I was just wanting some clarification. Is the horsepower from a 1988 Force 50hp different from a 1988 Mercury, Evinrude, Johnson 50hp?

 

[roscoe]

Yes, the Evinrude, Merc, and Johnson motors were rated at the prop by 1988.
The Force motors were not.


The the first three were 50 hp at the prop, +/- 10% per the manufacturing standard. So, 45-55 hp.

The Force was about 44hp at the prop, +/- 10%, so 40-48 .

But that was when they were new. Now that they are 30 years old, probably not one of them puts out 40 hp.

 

[jerryjerry05]

IF?? the compression is still at 145-150# the HP should be the same.
They don't loose power as they get older(unlike me).

​The older Forces, my 85's were actually 90hp.
​The 125 was actually a 120.
The 50 was a 50

​The Forces were touted to have the best HP to weight ratio.
​In 1986 the 85 1986 set a speed record of 81mph.