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MG Midget and Sprite Technical - carburettor overflow

I have just replaced the head gasket and in the process taken carbs off. since putting back together, there is petrol dripping from the overflow from the first carb. . . any ideas what has happened/what i have done?
d j kirk

There is a small "needle valve" in the float bowl that allows fuel into the bowl. This is obviously not sealing correctly and fuel is "flooding" the bowl and coming out of the overflow, this is very bad!

The valve is closed by a float inside the bowl that pushes the valve closed, somewhere you have a problem Either with the float (stuck, punctured) or the valve is damaged or has dirt on its seat.
Robert (Bob) Midget Turbo

You probably have some debris/sediment in the float bowl. In removing the carbs you probably didturbed this, and some has found it's way to the needle valve seat as Rob says.

If it wasn't overflowing before, then with the ignition on, but the engine NOT running, try tapping the float bowl relatively lightly with a screw driver or spanner. This may seat the valve and stop the overflow.

Better still remve the 3 screws, and inspect the interior of the bowl. Remove any dirt present. Remove the pin securing the float (carefully) and insopect the valve seat and needle. You will likely see a wear ring on the valve. If this is very prominant, you should replace both the valve and the seat. (Do both carbs to keep it even.

However. Prior to swapping to a single carb, my twin carbs had worn seats and valves for years. As long as they mate properly, they will seal when the float bowl is full and thus no overflow

But it can be a bit hit and miss, so as the float bowl kit is pretty cheap, I suggest if you do discover wear, buy a kit and replace the valves and seats both sides.

PS DON'T drive with a leaky float bowl. You might be lucky, I was frequently, but you will have petrol dripping onto your very hot exhaust down pipe. Not the best thing in the world imo. :)
Lawrence Slater

Working well again thnx
d j kirk

Great stuff. Beam us up scotty.:)
Lawrence Slater

was it the tapping wot dun it or did it just go by itself though
N Atkins

Actually petrol is'nt that dangerous, compared to brake fluid. petrol vapourizes, brake fluid ignites upon splashing on hte hot exhaust.
Alex G Matla

Its amazing how common this issue is becoming,

We need to put a header at the top of the site that says .... If your carb is leaking fuel out of the float chamber cap... Ect ect

Yeah know all joking aside... A little link of the 10 most common ... It wont start issues ... Of how to diagnoise and fix would be a really good idea
Anyway... Good luck, im sure its sorted by have fun and enjoy the smile

Yeah but Prop, ---

If you did that, ---- and I agree it would be a useful idea -- there wouldn't be much left to talk about.

It's fun sometimes reading the questions, and some of the answers are even more interesting than the correct solution.

It's the same with the Archives. Most answers are there, ---- if you can get past some of the bad titles -- , but it's more satisfying to ask the question all over again.

I'd be willing to bet, that if there were a link as you propose, peeps would still pose the same questions rather than follow the link.

At least I hope so, because I like a good read and sometimes a laugh, with my morning cup of Cha. :)
Lawrence Slater

Yeah, i suppose your right lawerance... But perhaps we could have an on line race car game with nothing but midgets in order to burn up the extra band width and time.


This thread was discussed between 11/10/2011 and 16/10/2011

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