On Thu, 09 Aug 2007 20:48:16 -0700, sonofadocker
wrote:

1976-1983 JOHNSON SEAHORSE 90 HP MOTOR.

I SPUN THE ORIGINAL PROP AND HAVE SEVERAL OLDER SPARES.

I HAVE LOST SPEED AND CAN NOT PLANE ANYMORE.

WHAT SIZE PROP SHOULD I USE.

The original prop for that engine was 14"X13p.

That's the original recommendation.

That doesn't mean that's what you had based on what you stated.

In theory, at 5K , which is in the middle of the operating range for
WOT, with the original prop, you should be doing something nearer to
40 mph.

If you have the prop you spun, look in the exhaust side and the size
and pitch will be stamped on the hub. That will tell you what you
had. (Sometimes, the size and pitch will be stamped on the prop itself
- you might have to look around for it). Then you can compare the
prop you had to what was spec'd for it originally.

It would help to know the size and type of boat.