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MG TD TF 1500 - Carb Spurting Fuel

Hello Everyone,
The carbs on my TD have both, at different times, spurted fuel out of the pin assembly on the float bowl. I'm alerted to this by hearing my fuel pump not shutting off after turning on the ignition. I then turn off the ignition, lift the bonnet, tap around the float chamber with the end of a screw driver, and give it another try. This usually solves the problem. I don't know what's causing this or how to solve the issue. I don't like to be nervous every time I go to start up. I'm assuming the float is getting stuck. Does anyone have any insights or suggestions for me so I can have more reliable start-ups?
Thanks, Tom
T Scileppi

Check your float valves for debris.
Christopher Couper

As Chris says, it is sticking in the float-pin-needle-seat assembly. Pop the top and clean it out.

Instead of whacking the float bowl, see if you have pins to depress in the top of the floats to "tickle" the float, depressing the float down to "pass gas." That might free a sticking float.

Here is a Technical article that describes the modification to the Float lever(new ones from SU come with slots cut). This is from late Dave DuBois documents captured by Dave Braun. Titled" Float Lever Drop Adjustment
Richard Cameron

I know mentioned by others before but I highly recommend the youtube submissions by John Twist of University Motors. His coverage of a good deal of the intricacies of our T series cars including the SU carberetors are in my opinion a must viewing not only those new to our cars but as a reminder of those things we have-or I have, forgotten. For example
JK Mazgaj

Above problems common. I had similar problem when the car would sit for a few weeks and all of the fuel would evaporate. The float and chamber were gummed up and the float would actually stick down. A good cleaning fixed it. George
George Butz III

These carb are designed to function on barely a few psi fuel pressure. We have to assume you have a typical fuel pump. Electing to go to a newer fuel pump with higher pressure can overpower the needle and bring on overflow.

Thank you to everyone who offered suggestions. I had the carbs rebuilt so I expected everything to be fine. I watched the video by John Twist, tried watching the one by Dave Braun but it wouldn't come up. I'll try cleaning the float valves and see what happens. Thanks again.
T Scileppi

I had the same problem. After many cleanings it went away when I changed the float.

Disconnecting the fuel pump and letting the bowls run dry is also a good thing to do when leaving the car for a while.

J Barry

I am not certain of the exact make up of the TD float mechanism but on a TF there are tabs on the needle valve forks that prevent them falling too far down when the float chambers are empty - eg when the car has been left standing for sometime. If they drop too far down they can bind on the float needles and prevent the floats lifting and thus causing overflowing.

Jan T
J Targosz

This thread was discussed between 05/06/2019 and 07/06/2019

MG TD TF 1500 index

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