MG Car Repair: 78 MG Midget Smoking, temp gauge, float chamber

Question
I'm back again but this time with more information on the smoke that I  thought was originally thought was coming from the air filter and then the carburetor.  After taking off the air filter to figure out where the smoke was coming from I found the end of a pipe below the carburetor that is definitely the culprit.  It looks like an exhaust pipe that is not attached to anything.  It whistles and lets out white smoke.  The car starts up and drives fine for about two miles which is when smoke will start coming inside the car and out of the hood of the car.  The temp. gauge is low until you turn off the car which is when it raises considerably and becomes hard to start.  After about an hour of sitting it will start back up again no problem and with no smoke until it is ran for a while again.

Answer
Brandan, look at the pipe and follow it to where ever it goes and tell me where it goes to.
It is normal for the temperature to raise when you turn the engine off.
When an engine is hard to start just after a shut down it can be from two reasons. One is that sometimes a float needle will leak the residual fuel pressure between the pump and the carburetor and this extra fuel will flood the engine on a restart.
Another possible reason is that the under the hood temperature is high normally but when the car is shut down, no air is circulating so the temperature climbs higher to the point it boils the fuel out of the carburetor and it takes some starter spinning to refill the float chamber.

A method to test which is the problem is to preset an electric fan in front of the car where it is parked and drive the car until you are sure it will have a problem and stop in front of the fan and shut the engine down and raise the hood and let it sit for the amount of time for a restart. If it starts right up then it is a high heat under the hood problem.

The normal repairs for this type of problem is to wrap the fuel line from the pump to the carburetor and to fabricate a insulating heat shield to keep exhaust manifold heat off of the carburetor.

If it is the other problem of too much fuel you should try on a restart to hold the throttle open more to let in more air so the excess fuel can vaporize and thus start. This is a standard method to start a flooded engine.
Howard