MG-Cars.net

Welcome to our resource for MG Car Information.

Recommendations

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG MGB Technical - Fuel leaking from run on valve

Hi,

I just got my MG electrical problem fixed (it was refusing to start - faulty ground) and when the fuel pump finally started ticking fuel began to pour out of the anti run on valve and around the cannister filter.

Does anyone know why fuel might be pouring out of the bottom of the valve? Also, is there supposed to be a hose from that valve somewhere?

It is a 1973 MGB US Spec with no air injection pump, all other emissions components are properly connected.

Thank you
Adam

Adam,
one (or both)of the float bowls is probably overflowing. Disconnect the hoses from the bowls and turn the ignition on, you'll quickly see which one is causing the trouble.
HTH,
Rufus
Rufus Pool

Adam,

Check that the output side of the fuel pump is not connected to the tank vent line. The lines run side by side and although the vent line is usually longer, it could have been shortened in a previous life.

Doug
D. Cook

This overflow will also occur if the feed pipe is connected to the inlet port on the carb(s) but the vapour line/running-on control pipe to the canister is blocked.
Paul Hunt

Adam,
That symptom turned out to be BOTH carb floats on my '73 BGT. Both of them were full of fuel. If you didn't work on any fuel-related stuff when you were doing the electrical fix, I'd bet it is the floats.

Pat
Patrick Callan

This thread was discussed between 26/12/2004 and 31/12/2004

MG MGB Technical index

This thread is from the archive. The Live MG MGB Technical BBS is active now.