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Fuel cut-off valve


Freshman Member
All the talk in this forum lately about fuel lines (especially where the word fire has been mentioned) has inspired me to change out the fuel lines on my "new" '80 B. The PO ran the fuel line from the fuel filter on the firewall to the carb, but I see that there is a shut-off valve in there too. I'm wondering what the valve does, and what the consequences of using/not using it would be. If anyone has any experience with this and can enlighten me I'd appreciate it. Seems the more I learn from you all, the more I realize I don't know.



Staff member
Country flag
The shut-off valve is designed to stop the flow of fuel in the event of an accident. You could by-pass it, but then if you have an accident and fail to switch off the ignition the car will continue to deliver gasoline to the carburettor.

Welcome to the BCF! If there any other questions you may have, just fire away.


Jedi Knight
Welcome to the Forum from another PAer! /ubbthreads/images/graemlins/cheers.gif

If it is a manual cut-off valve, the reasoning may be like this...some people like to be able to shut off the flow to the engine when putting the car into storage for a while. You can shut off the gas supply and run the gas out of the carbs to avoid evaporation, siphoning and sludge forming in the fuel system. I think that a few ounces of Stabile or other gas stabilizer before you store the car for a while, allowing time for the engine to run some treated gas into it, provides better protection.

Bruce /ubbthreads/images/graemlins/driving.gif


Freshman Member
Thanks guys...be careful when you say things like "If there any other questions you may have, just fire away." to someone new to the MG (I did have another 'B' back in my late teens, when I was too young to appreciate it and not car smart enough to work on it...I have half of that back now, as I appreciate the British cars in general and the MG in particular. Now all I have to do is learn how to get [and keep] mine going.) I hope to pick all your brains frequently!
Gary /ubbthreads/images/graemlins/laugh.gif


Jedi Knight
Seem from where you describe the location of the switch a PO might have used it as a "anti-theft device".

Welcome to the forum. Its a friendly, helpful lot.


Jedi Knight
Country flag
The OEM fuel cut-off valves have an annoying (and dangerous) tendancy to leak. IIRC, there is also an electic shot off valve under the dash. You only need one. If you want to replace the one under the hood, consider an aftermarketone.
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