Re: Re: Re: Motor Rating

[ Ol' Paw's Boat Motor Bulletin Board ] [ Ol' Paw's Fishing Page ]

Posted by Ed Mc. ( on July 20, 2005 at 21:21:57:

In Reply to: Re: Re: Motor Rating posted by Ken Denman on July 20, 2005 at 17:01:22:

Abolutely Not Correct!!!

Most motors were rated at the crankshaft until the Mid-Eighties!

You telling me that a 1973 Merc 115 HP small-port, non-power-ported Inline Six produces the same HP at the prop as a 1988 Merc Power-Ported 115 Inline Six??? I think not!

A late-model 115 Merc Inline has about the same guts as an older crank-rated 1400 Merc.

Johnson and Evinrude downrated their 3-cyl 70 HP to a 60 HP at the prop, and brought out a larger C.I. 3-cyl which was rated at 70 HP at the prop.

These are just a few examples, there are plenty of other motors which were downgraded when the mfr'S transitioned from Crank-rated to Prop-rated HP.

The NMMA (National Marine Manufacturers Association) is in charge of setting these standards.

Before the NMMA there was the Boating Industry Association of Chicago (BIA) and the National Association of Engine & Boat Manufacturers of New York (NAEBM), both of which merged in 1979 to form the NMMA.

The NAEBM had been around since the turn of the last century, a lot longer than the now-defunct NOA.

As far as I can recall most motors conformed to B.I.A. standards prior to NMMA.

Durafix Aluminum Repair Rod Demo

See Items Repaired With Durafix