The HS-15 is an alternate firing 2-½ horse power Johnson built in 1940. It is the Plain Jane version of the HD model that was built through 1951. (A smaller version of the 5 horse TD model.) It runs at higher speeds as a third port motor with the carburetor on the starboard side. Pushing the high speed fuel adjustment primes the outboard through the low speed jet behind the fuel tank. At idle it runs off a rotary valve in the center bearing with the idle adjustment under the fuel tank by the stearing handle support bracket. Compression should be around 65 pounds PSI. The J8C Champion spark plug is gapped at .030" and the magneto breaker points are set at .020". It has all bronze bushings and should run 30 wt. non-detergent oil at a half of a pint to the gallon. The lower unit gear case uses grease. . . 😉
