Fuel Pump servicing
1988 Johnson/Evinrude 40HP - 55HP models
Before replacing a suspect fuel pump, remove and clean the fuel filter and install a new filter element. Also remove the fuel line from the fuel tank and blow through all passages and lines with low-pressure, compressed air to be sure they are open. This may be the cause of inadequate fuel delivery, and if so, would eliminate unnecessary replacement of the fuel pump. If this procedure does not correct the trouble, fuel pump is probably malfunctioning and should be replaced.
To install a new filter element, remove the screw "A" retaining the fuel pump cover to the fuel pump. When installing the filter element "B", place the lip of the element toward the gasket "C". Install the fuel pump cover and tighten the screw securely.
Testing Fuel Pump
Conduct this test on the motor in a test tank or on the boat.
Before testing, loosen fuel tank gas cap momentarily to release any pressure that may have built up. Fuel tank must not be more than 24 in. (61 cm) below fuel pump.
- Remove carburetor to fuel pump hose. Connect a fuel pressure gauge (obtain locally) between the carburetor and fuel pump.
- Start motor and observe gauge. Pump pressures should read as below.
600 RPM: 1 PSI / 7kPa 2500-3000 RPM: 1.5 PSI / 10 kPa 4500 RPM: 2.5 PSI / 17 kPa - If fuel pump does not meet these specifications, replace fuel pump.
Updated on: Wednesday, November 11, 2020