MG Car Repair: Car wont start after being used., rich mixture, reflective heat

Question
I recently bought a 1970 MG-B - my first MG.  It has dual carburetors ("British Leyland - a Coopers Product").  It always starts when cold, but will seldom start after it has been warmed up.  Do you have a solution to my problem?
Thank you!

Answer
Hi Jim
Sounds like the carbs are set much too rich.  

(The following was edited to remove jargon)...

Does the car run smoothly when warmed up?  When you are stationary and the warmed-up engine is idling, does it have a regular sound or is there a rhythmic speed-up and slow-down (thrum, thrum, thrum)?  That is known as `hunting' and is an indication of an excessively rich mixture.

Another possibility is the dashpots on top of the chambers.  Have they got oil in them?  They do need topping up regularly.

If the problem only happens in hot weather, it might be that the float chambers or the fuel lines are getting too hot and the fuel is vapourising.  This is known as `heat soak'.  Sometimes you need to re-route the pipes or add a reflective heat barrier.  Has your carburetter heat shield lost its asbestos backing?         

Let me know how you get on.