How to Check a Fuel Pump on Fuel-Injected Outboard Mercury Boat Motors
- 1). Look at the sight glass on the fuel pump. If there's fuel in the sight glass, the pump's diaphragm is ruptured. To avoid a fire on your boat, replace the fuel pump before doing anything else.
- 2). With an open-end wrench, disconnect the hose that runs from the fuel pump to the fuel rail which supplies fuel to the injectors. Set a five-gallon plastic bucket beneath the hose.
- 3). Turn the ignition switch to the "Run" position on the key way. This will cause the electronic control module (ECM) to turn the fuel pump on for two--and only two--seconds. Listen for the whirr.
- 4). Tell your assistant to lower the hose from the fuel pump into the bucket. Tell your assistant to let you know if fuel begins to pump into the bucket.
- 5). Continue turning the ignition switch until it reaches the crank/start position. The ECM will turn the fuel pump. Fuel will be pumped into the bucket, if the pump is working.
