Hi James. Your Johnson 15 should be a 1956 model FD-10, the only year Johnson made the 15 before upping it to 18 horse in ’57.
This carb has two small holes on the body itself, on the choke side. The top one is an air bleed for the idle circuit and goes straight in horizontally. The one slightly forward and below it goes in at an angle, about 45°, and is the bowl vent. Is the fuel coming out of either of these two holes?
The air silencer fastens to the front of the carb and any fuel dripping out of here would be cosidered normal after choking. Fuel dripping out the rear of the carb where it fastens to the motor would indicate a damaged or missing gasket.
Was the sediment bowl gasket replaced during the rebuild? They tend to leak as they get brittle and cracked with age but aren’t included with the OMC/BRP 439071 carb kit required for this motor and must be purchased separately, P/N 303122.
NOTE: Rope start motors have the sediment bowl on the bottom of the carb bowl while electric start models have the sediment bowl mounted remotely on the port side of the motor.
