Fuel Pump on Injected vs Carb engines
Asked by: Ticen 1859 views Aircraft Systems, Flight Instructor
Sorry if this question seems rather "basic". On Carb engines with low wings, mixture often goes to rich and fuel pump remains "on" during start. On injected engines, pump is on for a few seconds, then turned to "off" , mixture brought back to lean and advanced to rich on start.
Why does a carb engine not get flooded (pump remains on during crank)? And if you prime engine and then squirt a full prime directly into cylinder as you crank, why do we not pull mixture back to lean as we do on injected engines on start to avoid an engine fire on start?
I understand on injected engines, the injectors could get flooded if left on for too long (but that brings up a follow up as to why fuel does not stop flowing when a certain pressure is reached; I believe autos have that function for you hear pump turn off a few seconds after you turn a car key to accessory position)
I think I have 3 questions buried in there haha