Example #1: 1975 Johnson 9.9 Short-Shaft
This is a stock 1975 Johnson 9.9 on an 11' inflatable boat. The propeller is 9 1/4" diameter x 8" pitch. (Stock is 9 1/4" x 10") Top speed is 20 mph on the GPS.
Example #2: 1983 Johnson 15 Short-Shaft
This is a modified 1983 Johnson 9.9. We performed the full conversion to a 15+hp including the carburetor, leaf-valve spacers, and polished 15hp exhaust tube. This engine turned out to make so much power that we had to INCREASE the propeller pitch to the maximum offered 11" (9"x11") to keep it from over-revving.
This is on the same boat as the first video with the same driver and equipment. Top speed is 27 mph on the GPS.
This is on the same boat as the first video with the same driver and equipment. Top speed is 27 mph on the GPS.
