Saturday, December 19, 2015

Generator Fuel Pump


If you remove the generator access door and look at the carburetor, towards the bottom is a largish head screw. This is the carb bowl drain. Draining the carb bowl during storage goes a long way in keeping the gen-set happy. When loosening or removing the screw, a little gas will drip down - just put a small bowl or paper towels down to catch it.

With the gen set prime/start switch right there on the unit, you can push the prime button and instantly see if the bowl is filling up again. Without taking anything else apart, this will be an aid in troubleshooting. You can hear the pump working, but if there's no gas entering the bowl, the first thing to check is the main fuel tank level. Is it above quarter full? Next would be the fuel shut-off solenoid at the bottom of the carburetor bowl. The solenoid has two wires going to it, ground and positive. You'll need to remove the wires to unscrew the solenoid. The ground wire is fixed to the gen frame right in front of you. The hot wire has a spade connector that will be revealed by pulling it towards you. It is easily cleaned of gunk and put back in service - no parts needed. Last reason for no gas would be a break in the fuel line from the truck gas supply.

When I did mine, I removed the whole carb to get at everything, as I didn't know it was just the solenoid causing the no run problem.  The carb bowl can be removed without removing the carb itself. Take care to note where all the washers are located.

Edit DHM There is probably a just right wrench for removing the carb bowl. I had to use plumbers pliers.

If you get in the habit of draining the bowl before long storage, a gunked up fuel solenoid should not be of concern.

BTW - The reason for the recommended monthly gen set run is threefold. To heat up and dry the generator windings, to exercise the motor, and importantly to re-magnetize the generator's stator core. It is the residual magnetism in the core that allows the gen to start making electricity. If left too long without running, one may need to "flash the windings" to get the generator to function again. (Doable with the "flashing coil with two drill motors" trick (search Youtube using that term for instructions).

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