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MG MGB Technical - Fuel pump problem?

I've just put in a gallon of petrol for the first time in 5 years to test the fuel pump etc. When I switch on the ignition I can hear a single click from the pump, then nothing.
The pump is an after market 'electronic' unit that I know was working all those years ago, but we all know that shelves can have a serious effect on stored items!
I was wondering if I needed to prime the line from tank to pump so that the pump has something to 'move'? Any other ideas please.
Richard Coombs

Richard - disconnect the inlet line from the pump and then turn the ignition on and see if it will run. Priming the fuel line will probably not result in the pump running correctly - it will just add more resistance to the pump's operation. My bet is that the pump is past its pull date. Cheers - Dave
David DuBois

These reciprocating pumps will run with or without fuel, chattering madly with no fuel, more slowly when pumping. They are also self-priming.

Sounds like the solenoid is operating, but the electronics are not cutting the power to it when it has done so. That is exactly what happens to the points pumps when the points get spiked and stick together. Could be something is preventing the diaphragm travelling as far as it needs to to switch the electronics, the magnet (if the plastic-bodied Moprod type) has come loose, or there is a fault in the reed switch or electronics. My Moprod was a pain, eventually had to replace it with a points-type.

If it's a rubber bumper at least you can remove the cap from the electronics end and see what is happening, if a chrome bumper it will probably have to be removed. Ironically the rubber pumps are higher and don't siphon when you remove the pipes as long as you keep the ends high, but the chrome bumper pumps will siphon. However if chrome yours may not have pulled fuel far enough to do so, if it does slacken the connection between the pump pipe and the tank (hold the block on the tank with grips while turning the nut) and it will break the siphon.
PaulH Solihull

This thread was discussed between 06/04/2012 and 07/04/2012

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