fuel leak from back carb

[derek boghurst]

Hi, I have a 1977 MGB GT, which is great apart from some times the back HIF carb leaks from the over flow. I take the float chamber off and the float appears to work OK, I happened today when I had the the ignition on but the engine not running. The pump tick stopped, then started again slowly and the fuel came out of the over flow. Could it be the pump, can you adjust them, or should I change the jet and float?

[Peter Cresswell]

Hi Derek
Most likely cause is a worn needle valve in the float chamber as this shuts off the fuel flow as the float rises. Less likely, but check in case, is a puncture in the float itself. If you take it out and shake you will be able to hear if it has fuel inside.

Other people have had similar problems so take a look elsewhere in the forum. I have found some to start you off:
http://mgbforum.mgb-register.org/viewto ... ?f=4&t=142
http://mgbforum.mgb-register.org/viewtopic.php?f=4&t=66
http://mgbforum.mgb-register.org/viewto ... ?f=4&t=261

Many cars appear to be starting to see the problems associated with ethanol in the fuel, and if your flexible fuel lines are still the originals it is worth considering changing them for ones that are suitable for ethanol. With the show season now in full swing it is a good time to look for some bargains where you can speak to the supplier. I would recommend a complete kit if the stainless braided type.