D. Testing Petrol Supply between Tank and Autovac
Yes. Close the throttle and turn the engine with the electric starter for a few moments. This should suck petrol from the tank into the autovac. Wait a moment a two for the petrol to flow, then open drain cock B. If the autovac is still empty, the fault lies either in
(i) The suction system of the autovac, or
(ii) The petrol supply pipe from the tank to the autovac.
The former is the more likely alternative, and the probable seat of trouble is the autovac drop valve failing to close under the suction. Therefore, release clamp E; remove one of the pipes; pour petrol into autovac in order to flush the valve. If sufficient petrol is poured in it will also fill the carburettor float chamber and enable the engine to be started immediately. If the petrol supply fails again, stoppage in the petrol apply to the autovac is more likely to be the cause.
E. Clearing the Petrol Supply System between Tank and Autovac.