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MG TD TF 1500 - gas comes out of first carb

When I turn on the key the fuel pump starts working and gas sometimes comes out of the top of the first carb. When I turn the key off and on again it does not do this. Is there a check valve that is stuck in there? How do I fix this probler. The Carbs were probably original in a 1950 TD

Thanks
Tom

Tom,
This sounds as if your float needle is sticking. Turning the fuel pump on and off is somehow "jiggling" whatever is holding the float needle open. Open the float bowl up and look for the cause. Clean the needle in solvent. Sometimes this is all that is necessary, but the best cure is to replace especially if many miles or lots of time has passed. Ben
Ben Cordsen

Tom

What kind of fuel pump do you have? The original pump is a low pressure fuel pump that puts out about 3psi. A high pressure pump,around 12psi can over ride the float needle valve causing an overflow.If the pressure is to high, you will need a pressure reducer between the pump and carb.

Regards Ermit
Ermit Starnes

Tom - If you are experiencing this problem after the car has sat for some time, then what is happening is that the float bowl is drying out, allowing the float to go clear to the bottom. This allows the lever at the top of the float that controls the needle valves to drop down far enough that it jams against the needle instead of pushing it up. After turning the key off and allowing the pressure from the pump to subside a bit, everything usually settles itself out and starts working again. The fix is to either adjust the drop on the lever (not shown in the book and beond the scope of this venue) or install Gross jets (available from Moss or Abingdon). Unless you have an aftermarket fuel pump, I doubt that the pump pressure is high enough to cause a problem. The low pressure pumps (original on the TDs) has an output pressure of 1 - 1.5 pounds and the high pressure pumps are 1.5 - 3 pounds (not high enough to cause a problem). If you will contact me privately, I can let you know how to adjust the lever to limit the drop. Good luck - Dave
David DuBois

This thread was discussed between 11/03/2001 and 12/03/2001

MG TD TF 1500 index

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