Join Date: Jul 2003
Thanked 0 Times in 0 Posts
Rep Power: 0
I am trying to nail down a fuel starvation issue on my A4. Here is the setup: tank >priming bulb>Racor>fuel pump>in-line filter>carb. I have the manual from MMI and followed the manual's suggestion for spring start-up and unscrewed the main passage plug on the carb and manually operated the fuel pump. Very little if any gas came out when pumping (I don't know what to look for here ... lots of fuel or a little. There was barely a dribble). I then removed the fuel line on the intake side of the carb to see if the in-line filter between the pump and carb was the culprit. Lots of fuel there. Next, pumped 1 litre of fuel into a container - clean gas - no water/etc. Then put things back together and tried the engine.
I primed with the priming bulb and pressurized the system. I didn;t see any leaks (but this was at night using a flashlight). With full choke it cranked 1.5 seconds and started. Let it idle for 15 seconds reduced choke and the idle rpm picked up and smoothed out as per normal. At 25 seconds removed all choke. Then around 30 - 45 seconds or so the idle increased again for a moment (just a subtle increase). Then decreased (again subtle), then went back to normal. Sort of a wavering, but nothing severe (normal I thnk?). Continuing, Around 90 seconds it started to falter, I increased throttle a touch, but to no avail. It sputtered and stalled. As a note - I did have a priming bulb between the tank and Racor, but removed this as the quality was awful and it was a source of air leaks (cheap parts yeild cheap results). I retried the system and again, after 30 - 40 seconds it runs out of fuel. Hence .... I suspect air infiltration. I have a cork gasket on top of the sediment bowl and actually have a spare. I will try that. But I am curious as to the amount of fuel I should expect to see through the passage plug? Any help or suggestions would be appreciated.