Fuel Pipes

[philt1234]

Hello again

My engine is fitted with twin Strombergs/Solex. The fuel supply pipe feeds the first carb then across to the second carb on 1/4" pipe. On the connection to the second carb there is a take off with a smaller pipe (probably 1/8") coming off. What is it and where does it go to?

Rgds

Phil

 

[Rumblin_Ron]

Hi Phil

The pipe is the petrol return pipe to the tank. When the SU/Solex carb float chambers are full a valve shuts off the petrol. The mechanical fuel pump pumps all the time the engine is running, this petrol needs somewhere to go, hence the return pipe.

Many cars with SU carbs use a SU electric fuel pump ( ie MG's and Mini's), this has a pressure sensor that stops the pump pumping when the float chamber valve shut.