P.S. That is a model 4438 Fastwin – I had trouble with the rubber motor mounts twisting out of place and put a very short sheet metal screw in each to help hold them in place. It uses a Tiltson MD carburetor. The low speed adjustment adjusts the air. The idle tube supplies a set amount of fuel. It is also easy to clog up with stale oil. The gearcase was also used on the ’49 and ’50 QD Johnson. . . 😎
