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MG MGB Technical - 72 B FUEL PUMP

1972 MGB. Runs good but pump never seems to stop. No fuel leaks.
Pump seems to hum rather than click-click.

Hello Sandy,

Do you know if it is an original type SU pump? An SU can continue clicking without leaking when some valve in them leaks (I believe back to the tank). But, I have not heard of them humming, though I have never had the solid state type SU. There are some generic pumps that continue running. I think the Facet does, but I believe it also clicks.

C R Huff

This is a totally origina one owner car with 52000 miles.
I have not seen the car today but the way he describes it as if it is either pulsing extremely fast or humming. I will see it tomorrow.

Sounds like the pump is short stroking and the valves are shot - that would be just about the only thing that would cause it to hum. I have seen some of the all electronic pumps do that, but not the original points style pump. It could also be a diaphragm that is stiff as a board that will sometimes cause that. Cheers - Dave
DW DuBois

Sandy & Charlie. My 79 has the the SU fuel pump with the solid state electronics. It ticks just like the original dual point set up.

Curious to know if your fuel pump is the original one.


gary hansen

I may get to see the car this weekend. I will keep you informed.

When mine (electronic!) was short-stroking it resulted in severe fuel starvation such that it wouldn't run. Intermittent, so eventually replaced with a points type and no more problems.
Paul Hunt

This thread was discussed between 23/06/2015 and 24/06/2015

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