Welcome to our resource for MG Car Information.



MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG MGB Technical - Carb and fuel problem


Just recently posted a post about starting my car after a long time.

Was going to do it but having turn the ignition on and leaving it for a while till the clicking noise form the fuel pump slowed down and give it a wash. I noticed fuel was mixing with the water running under the car. Checked around and opened the boonet and noticed next to the carbs a unit that is either side and has a pipe running into it. There is another bit that looks like a pipe could attach to it but there is no pipe and fuel was slowly dripping out of it and down through to the floor.
Before i stopped using it for a while i had a garage put a new fuel pump in, fuel tank and hosing. It also had its carbs reworked and set. I am guessing there should be a pipe that runs between the two? it doesn't seem normal. Also i should point out before i stopped using the car i did a run to london that takes normaly 2 hours, on the way up the car cut out twice then restart as i was on the motorway as if the fuel had been cut. On the return journey i start off ok then it would cut out then i would grind to a halt then after a while it would restart. After i while i admitted dfeat and got the RAC to tow me home. I thought it might be the carbs not set up quite right and had to garage the car as i was going away. Worried now as it seems i was driving around with fuel leaking around the engine.

Is there a hose that should be connected between these two parts? Sorry for the long explanation and poor description but any help given i would be gratefuly accepted. i have a photo of it just not sure if i can post it up here?

Thanks for looking.
NJ Rawlings

I should have pointed out it is a 1971 Gt and the bit i am talking about is on the side of the Su Carbs one either side ( if this is of any help).
NJ Rawlings

From your description, the fuel is leaking from the float chamber overflow. This means that the needle valve in the lid is not sealing once the chamber (reservoir) is full and could mean they need cleaning, replacing, or the float itself is leaky and full of fuel. Whatever, as you have guessed, this situation is DANGEROUS as the fuel is leaking onto the red-hot exhaust manifold. The overflows should have pipes attached that direct the fuel away from hot bits, and these should also go onto your shopping list. The lid to the chamber is held on by screws so access is easy.
Steve Postins

Thanks for the reply steve where exactly will these pipes lead the fuel to? does it go back into the system or do the pipes just point to the floor away from the hot bits?

Thanbks again
NJ Rawlings

On my 67 the pipes simply empty out below the exhaust manifold. Later models may have had a recovery system. Don't know. The upper end of each pipe attachs by a short clamped rubber hose to the overflow nipple of each carb.
charles updegraph

Judging from the picture books 67s had tubes to keep the gas away from the header. I know my 67 had something, whether original or not. MG engineers may have done some funky things I don't agree with but I don't think they were too stupid not to put overflow lines on the carbs to keep fuel away from the header.

I have seen far too many MGs running around with no overflow tubes and it's a disaster waiting to happen.
Mike MaGee

This thread was discussed on 31/08/2005

MG MGB Technical index

This thread is from the archive. The Live MG MGB Technical BBS is active now.