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MG Midget and Sprite Technical - fuel problems

Help needed got a midget 76 been running smoothly took it for 50 mile run then a couple of days later started in garage run out of fuel since filled up car wont start will run whilst squirting fuel down the carbs
m barfoot

If squirting fuel down the carbs lets the vehicle run then the fuel is not getting to the carbs

I would imagine you will have a mechanical fuel pump. Disconnect the pipe that runs between the pump and carbs and turn the engine over, Does fuel come out?
Robert (Bob) Midget Turbo

no fuel coming out
m barfoot

Take off the otherside pipe and turn engine over with your finger on the pipe, does it feel like it is sucking?

Can you blow down the pipe and hear fuel bubbling in the tank?
Robert (Bob) Midget Turbo

Possibly, but doubtful, the fuel pump just suddenly packed it in or the more than likely scenario is it's plugged up. Take it off and manually see if it pumps any fuel from a container. If it comes apart check it and see if the one way valves might be stuck open or the filter screen has debris in it.

However, before you do that, ensure your fuel line to the tank isn't plugged with some debris. Compressed air if available from the engine bay to the tank should clear that out. The fuel pickup line could have picked up some tank debris as the fuel ran low.

Last thing is the flexible line from the engine bay steel line to the steel line under the chassis could have broken.

I know it seems like a lot, but any of these will stop your fuel flow and are relatively easy to sort out.
Clive Reddin

Bob doesnt feel as though its suckin cant blow pipe cant reach it
Clive goin to check fuel lines
m barfoot

Just a thought. How much fuel did you put in it after it ran out? Might not be enough for it to pick up.
Clive Reddin

10 litres
m barfoot

Hmmm. About 2.5 gallons. Should be ok, more wouldn't hurt though just to be safe. A length of fuel line would be nice so you could blow through the fuel lines to the tank. Usually needs another set of ears to hear any bubbles.
Clive Reddin

blown through fuel line could hear bubbling in tank
m barfoot

clive if i take the fuel pump off and manually pump it will i need a new gasket
m barfoot

Try not to let your tank go under 1/4 full as, unless it is a totally new tank and fuel lines/filters, then it will pick up debris and this will cause problems along the way.

Clean everything out - and then fill the tank - and try again. Don't forget that the carbs need cleaning out too ;)!

The other possible, and this will be sorted at the same time, is that petrol can crystalise in the pipes if it's been standing a very long time, so, that's something else that needs to be avoided.

No worries though - all easily sorted and avoided in the future :)

Clive - does plugged up mean the same thing then? Think that's a lost in translation moment?! Another great divide in the language that unites us I suppose :(
rachmacb

Yep spund like time to remove the pump

However it is posible to remove the top of the pump whilst in situ and inspect the diaphragm and you will also be able to see if the actuating arm is operating when engine is turned over.

Robert (Bob) Midget Turbo

thanks for everyone's help going to test the pump tomorrow in situ let use know how i get on and rachmachb thanks for the tip about leaving 1/4 tank of fuel this is all new to me I'am new to classic cars learning as i go
m barfoot

I do a 'my usual advice to new owners' post with good adviceif you want it
Nigel Atkins

Yes, sorry Rachel. Yes, plugged here means the same as bunged there. However, it seems as if his fuel line is clear so that narrows it down to the pump.

A new gasket might be needed depending on how the other one comes off but I generally keep some gasket material in my tool box so if need be I can make one on site, but you might get lucky and it could be used again.

I feel that this will be a remove the pump and clean it out/inspect it on the work bench affair. Sometimes some small stuff like rust particles etc can get sucked in and that can keep one of the valves open preventing the pump from sucking in fuel.

Ideally, a fuel filter located before the pump and before the carburettors will prevent any debris from entering your fuel system. You may wish to check the fuel bowls on the carburettors for any debris just in case it got in.
Clive Reddin

Thanks for everyones help all sorted out now
m barfoot

for those that follow in your footsteps, what was the problem and how did you fix it?
David Smith

The problem seems to have been some crap from tank to pump took pump apart in situ diaphragm was working blew through fuel lines everything seemed fine reasembled pump attached fuel lines still woudnt work wasnt getting fuel from tank to pump even though pump was working then but pipe on outlet of pump siphoned then all was well so got car running fulled up with more fuel going to a fit couple filters on fuel line stop it happening again so thanks everyone for tips and help much appreciatted
m barfoot

This thread was discussed between 11/05/2011 and 14/05/2011

MG Midget and Sprite Technical index

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