Triumph Repair: 73 Spit wont restart, fuel vapors, float chamber

Question
Howard- I hope things are going well.  My 73 Spit will fire up nicely and then i drive it fro about 15 min or so.  When i park it and try to restart it, it needs multiple (10-20 times) cranks to get it going, then runs okay.  It does try to die while slowing down but overall runs.  It is not overheating or at least my temp gague does not say that it is.  I do smell gas when trying to restart it.  This is very frusterating becasue it was overheating which I think it under control afterI replaced the water pump, flushed the radiator, changed the temp gague, etc...
Any thougths would be greatly appreciated.  
Thanks, Ross

Answer
Hi Ross,
Your problem does sound like it is a fuel related problem, so you should start there. When an engine is shut down and then hard to restart it can be either starving for fuel or has an excess of fuel. There are several cars that suffer from this and here is how it happens.

First the engine and manifolds are hot when you shut down. This heat is well transmitted to the carburetors with no air coming in through the radiator etc. Fuel boils at a low temperature so the fuel in the float chambers starts to boil. Much of the fuel vapors escape through the float chamber vent. It however can not escape as fast as the fuel is boiling and producing vapor thus there is a pressure build up in the float chamber which forces fuel out the jet into the manifold. This wet raw fuel puddles in the carburetors and manifold and cools the manifold somewhat.

So now you return to your car to restart and find that the float chamber is almost empty and/or your manifold is flooded with wet fuel giving you a flooded condition.

To test which is your problem (or both) do this, run the car for a while and stop and shut down. Come back when you know it is about the right time for it to not start and remove the tops (both) off of the float chambers. Look at the fuel levels in both float chambers. They should be over half full. If that is not wrong drive the car again the amount of time that the problem usually happens and shut down and wait the normal time that it does not restart and this time try to start it but only just short of it starting (5 to 8 times) The objective is to duplicate the failed start and quickly remove all the spark plugs and note if they are wet. This is a flooded condition. You must do this quickly so any fuel on the plugs does not evaporate.
If they are wet try the restart procedure with the throttle on the floor. (Standard flooded restart procedure)

If your problem is empty float chambers then the cure is to replace the mechanical fuel pump with an electric pump. Some car manufactures went to the extreme of adding an electric fan that blew on the carburetor after the engine was shut down. Many set electric radiator fans so they would continue to run after the engine was shut down and several put insulation around fuel lines and heat shields between the manifolds and the fuel system.

It is no use going to any of those extremes until you ID the problem.
Howard