Mike,
sadly the front chamber does contribute.
With a top feed float (rear carb) the fuel cannot get back out of the float chamber (unless the carb is upside down!) into the supply line.
With the bottom feed, as soon as the level drops even a little - by evaporation or leakage say- the valve at the bottom of the chamber, below fuel level, opens allowing the fuel to empty back out into the fuel line, and rear carb which drips merrily away.
This emptying of the front chamber is the reason it seems to take forever for it to refill when you come to restart....a good long ten seconds should be allowed to get a first kick restart after a stop.
Tatty
sadly the front chamber does contribute.
With a top feed float (rear carb) the fuel cannot get back out of the float chamber (unless the carb is upside down!) into the supply line.
With the bottom feed, as soon as the level drops even a little - by evaporation or leakage say- the valve at the bottom of the chamber, below fuel level, opens allowing the fuel to empty back out into the fuel line, and rear carb which drips merrily away.
This emptying of the front chamber is the reason it seems to take forever for it to refill when you come to restart....a good long ten seconds should be allowed to get a first kick restart after a stop.
Tatty
