I have a 1998 Johnson outboard that has an internal fuel tank plus the connection in the front to attach an external fuel hose. This is all controlled by a selector knob on the front of the motor case. In the process of diagnosing why the motor will not start and reviewing all the fuel lines, it appears that the fuel pump on the side of the engine is only used when using an external fuel tank, otherwise fuel is gravity fed to the carburetor from the internal fuel tank, bypassing the fuel pump. Is this a true statement ? Engine just runs for a few seconds and quits. Carburetor has been disassembled and reassembled. Fuel in bowl, all jets and passages were clean. Good spark at plugs. Compression test around 90 lbs both cylinders. Would like to eliminate the fuel pump as a cause since I am using the internal tank on the outboard. Any ideas why it will not start would be appreciated.
