WSM does not say to have the engine running when opening the air vent cock and the Owners Manual does. Tried with engine running and did not fix problem as well as ran poorly. Tried without the engine running and fixed problem. Both books say it will run poorly if air vent cock is left open.
Do you think it is just and over sight in the WSM or is the WSM correct or by experience do both methods work/are correct.
Since the Bleed valve is located right at the injector pump block, and based on my experience when my L2501 died with the valve open, I feel that the valve should only be open for gravity flow to purge the lines, because if there is a little restriction through the filter and lines, air can be drawn back through the line from the top of the tank.
I do not have a schematic of the bleed valve, but guess that there are orings/ two positions where flow goes through to the injector pump and maybe second shunt position where flow baypasses and injector flow is off?? I guess I'll have to pull the valve stem off and look at the spindle to see? I do notice that both the filter has a auto-fill/bleed line on top with finger spring clip, as well as the finger spring clips on the Bleed Valve line. Both are attached near the top of the fuel tank. There is only about 15 inches of gravity flow head between the tank and the bleed valve depending on tank fullness..