78 MGB dies when warm

My 78 MGB does not want to inititially start unless I use starter fluid. Once started it runs fine until the engine warms up, then as soon as I leave off on the accelerator the RPMS drop down to nothing and it stalls. Even if I try to baby the accelerator it wants to die out on me. It will start right back up again, but I have to really baby it (mostly unsuccessfully) to keep it running. Any ideas??

Does the car still have the ZS carburetor on it?

Clifton

It has what I believe is the original Stromberg carburator.

I am thinking that the starting problem and the dies when warm problem are 2 seperate issues.
The MG will start without starting fuild if I pump the gas and grind the starter for what seems like forever. It is so much easier just to squirt a bit of starter fluid in it and away it goes. Once it is started, it runs as smooth and nice as can be. Idles good, accelerates ok.
It is only afer it is running for 15-20 minutes and the engine heats up that the motor wants to die. As long as I am going at 20 mph or above it still runs great. When I slow down to make a corner or stop, is when it just idles down to nothing and dies.

The choke is probably bad. That carburetor doesn't have an accelerator pump, pumping the gas pedal doesn't do anything. There is a diaphragm under the piston chamber cover that frequently fails. when it fails it will cause poor running as you said you have, check it for splits or damage, if bad replace it. The diaphragm isn't very expensive. The links below explain how to adjust and repair the choke.
http://www.paulbunyan.net/~jasko/choke/
http://www.theautoist.com/zs_water_chokes.htm

Another choice is to get a manual choke kit, expensive but some owners claim they solve the cold start problems.

Clifton