so if 12v is being given to the choke heater, why isn't it working. And musn't there be an earth involved somewhere as well?
Presumably, the idle-up solenoid works in exactly the same way as the anti dieseling solenoid, but the anti dieseling solenoid has 1 wire from it and the idle-up solenoid has 2, so therefor is it possible that 1 of the wires to the idle-up solenoid acts as an earth to the carb, which in turn affects the circuit for the auto choke heater?