Ransomes MG5 carb flooding

[simonc]

Hi folks, new owner of an MG5, I’m having trouble with the carb flooding. Basically when I turn the engine over on the handle to start petrol pours out of the carb overflow, and continues when it starts up. I’ve cleaned the carb, new float chamber gasket, replaced the float and needle and lapped in the new needle, at a loss what to do next. All ideas welcome!

[urbanalfa]

How much is it overflowing? Are you running the crawler on a hard surface?

As there is no suspension or engine mounts to absorb vibration I find they tend to shake a bit if run on a hard surface. Others with more experience may be able to explain why, but I’ve found it common to get fuel leaking from the top of the carb when the engine is idling and the machine is parked on a solid surface. If that’s the cause it should subside of you can drive it on something softer.

[simonc]

It’s a steady stream – and starts as soon as I turn the handle over, so not just engine vibration. It’s as if the pressure from the fuel pump is too much for the float and needle to hold, but not sure what else I can do to get them to seal better.

[urbanalfa]

In that case it sounds like you’ve already done what I would do.

Have you spoken to Neil Jarrett?

[expeatfarmer]

Sounds to me as if the valve in the fuel pump is stuck it should stop pumping when resistance from needle valve shuts off.

[simonc]

Thanks for the suggestion – that will be my task next weekend!

[simonc]

Thanks for the advice, pump cleaned out and new diaphragm put in for good measure. After a little fiddling with the magneto to get the timing right it now starts and runs nicely.

[Author]

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