Question: When taking my 1973 Silver Shadow for its fortnightly winter run, I noticed on returning (after approx. 10 miles) that petrol was being ejected from the overflow pipe located on the right side of the bellhousing. The amount could be described as "full bore". Switching off the engine stopped the flow, switching on the ignition started again. As it was dark and my garage is unheated I decided to tackle the problem the next day.
Engine started no problem, fuel leak, no sign. However the car has now a distinguised missfire, seems to be from the left bank and would appear to be petrol related as there are no signs of ignition problems.
So, where do I start to remedy this problem? Any help or guidence would be greatly appreciated.

Answer: This sounds like the float or needle valve has stuck in the carb allowing the fuel to fill chamber and overflow, this will cause a misfire as well due to incorrect fuel delivery.

Question: Problem is solved. However, the needle valve was OK! For some strange reason the hinge which closes the valve had stuck and depressed the float allowing the reservoir to overflow. Luckily I had a spare carburettor top! Thanks again