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MG Midget and Sprite Technical - CArb Problems

Need some help on my carb. My 1976 midget has been in storage for some time. I did use Stabil when I parked it and today I decided to start the car again. I noticed gas pouring out of the card from a tube that is located directly above the fuel line that goes from the pump into the carb. I obviously don't know what the problem is but I am afraid that the float bowl may be stuck. What are your thoughts and if that is the case what are the odds that I will get lucky and it will free up on its own? Thanks.

Rex
R. E. Hardy

Sounds like the needle valve has failed. It will need replacing.
Adrian

That is the overflow so you are right:

Needle valve worn
Need valve OK but blocked open with dirt
Float level set incorrectly
Float leaking and therefore not floating!
Float not pivoting correctly
Jeremy Cogman

'been in storage for some time' = stuck needle valve, if you are lucky tap the outside of the float chamber with a spanner or light hammer and it will free off. Or undo the 3 top screws, remove lid, float and valve, free it all off, refit and off you go (with a bit more luck).
David Smith

Hi, Rex!

Sounds like you have the single Zenith carb. Ditto the above, the float valve isn't closing properly, so instead of fuel flow being shut off at the proper level (think toilet tank float and valve), it's overfilling and running out the vent.

If you remove the carb and take the float chamber off the bottom, you can easily see if theres any crud in there. Make sure you get it really clean, and add an inline filter just before the carb. The float valve is in the carb body itself, and when the float rises, it presses against the valve pin and shuts it off. Or at least it should!

Please note that some of us, myself included, have had serious issues with the Grose Jet float valves. These use a ball seal instead of the original needle, and are known to work poorly and allow overflow. If your float valve has a steel ball sticking out of the bottom instead of a little brass pin, there's your problem. Replace it with a standard type.

Note also that if you let the car run for any length of time with the mixture way rich due to overflow, you might have allowed unburned fuel into your oil. Check your oil level and see if it's overfull... if so, it's got fuel in it, and you'll need to change it ASAP.

Best of luck, and keep us posted!

-:G:-
Gryf Ketcherside

Well the carb is no longer overflowing and luckily there is no gas in the oil. I did put about 4 gallons of new gas in the car and it will idle fine. I took it down the road today and it ran poorly but I am figuring that this may be because of the old gas that was still in the tank. Hopefully as I get to run it more and fill the tank back up things will smooth out. I am thinking that it should because everything ran fine when I parked it. Thanks for the suggestions.

Rex
R. E. Hardy

This thread was discussed between 26/07/2008 and 27/07/2008

MG Midget and Sprite Technical index

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