2004 SR Johnson 2-stroke 40, 50HP Service Manual, Page 140Get this manual
FUEL SYSTEM COMPONENTS
Fuel Pump
40R, 40RL MODELS
The fuel pump is diaphragm-displacement pump type operated by changes in crankcase pressureThe pump lifts fuel to the outboard and supplies fuel to the carburetor
The air motor diaphragm of the pump is driven by crankcase pressure and vacuumA pulse hose connects the pump to pulse limiter fitting that threads into the front of the cylindercrankcase
1Pulse hose 2Pulse limiter
The diaphragm of the pump is driven by crankcase pressure and vacuumA pulse hose connects the pump to pulse fitting that threads into the front of the cylindercrankcase