Johnson Evinrude Outboard Motors 1956-1970 1.5-40hp repair manual., Page 95Get this manual
TROUBLESHOOTING fuel pump, or by leak in the line from the fuel tank to the fuel pumpAged fuel left in the carburetor and the formation of varnish could cause the needle to stick in its seat and prevent fuel flow into the bowlA defective choke may also cause problemsWOULD YOU BELIEVE, majority of starting troubles, which are traced to the fuel system, are the result of an empty fuel tank or aged fuelFuel will begin to sour in three to four months and will cause engine starting problemsTherefore, leaving the motor setting idle with fuel in the carburetor, lines, or tank during the off-season, usually results in very serious problemsA fuel additive such as Sta-Bil may be used to prevent gum from forming during storage or prolonged idle periodsFor many years there has been the widespread belief that simply shutting off the fuel at the tank and then running the engine until it stops is the proper procedure before storing the engine for any length of timeRight? WRONGFirst, it is NOT possible to remove all fuel in the carburetor by operating the engine until it stopsConsiderable fuel is