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MG Midget and Sprite Technical - 1500 - Petrol in Carb Air Inlet

Just changing the air filters and noticed petrol in the carb air intake where the filters go on.

Been using some pancake filters and swapping them to standard paper ones.

Any observations from anyone appreciated.

Thanks in advance, Dave
Dave Squire

Dave it sounds very like a problem with carb set up. Have a look at the thread about "twin hs2 carbs" in this neighbourhood to give you something to start with. (But not the bit about the fuel pump ticking obviously).
Of course that is assuming you have SU carbs and haven't converted to weber or something like that.

I can't think offhand of a reason for pancakes to pull fuel into the intakes otherwise.
Greybeard

It does depend on how much fuel you are observing there. It is normal for a certain amount of fuel to be blown back from an SU carb into the air filters on the overrun, when the butterfly valve snaps shut. Evidence of a little fuel in the air filter is not unusual.
GuyW

Hi Greybeard,

Its as I thought. SWMBO birthday bash tomorrow so its going to be a valve timing and carb balance weekend next week. Its still twins and I have the kit and instructions.

Thanks for the confirmation I will let you know how it goes.

Cheers, D
Dave Squire

Oops, I was typing Guy.

Its more than a bit methinks but not so much that its causing a great problem. Might as well go at the settings. Its been a year.
Dave Squire

That's correct of course, but I'm not sure it's usual to see liquid fuel in the intakes more than a few minutes after the engine has been switched off. The little bit that might be there ought to evaporate quite quickly I think. But it does leave a bit of a stain on the metal.

As Guy rightly says, it depends how much is there.

Edit: Oops, crossed in the post!
Greybeard

All crossed postings!
No harm at all in going through a systematic carb set up procedure. But check and adjust valve clearances first.

Also, it may be worth getting the car up to temperature, doing an engine cut and checking the plug condition.
GuyW

This thread was discussed on 20/05/2017

MG Midget and Sprite Technical index

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