Boost pump ?Airlock?

[AviatorJ]

Rest assured I?m trained in fire safety. I agree it can be dangerous so I take precautions.

Anyhow here?s the process- I disconnect the hose from the mechanical fuel pump. I used an AN fitting which attaches to that hose end. On the fitting I have about 6 ft 3/4 clear tubing clamped to that.

The actual vacuum part I do with my hand on the end of the vacuum nozzle and slowly grasp the fuel line end and seal it just enough to get see some gas at the start of the 6 foot hose. After that I place the hose in a bucket and turn on the pump to verify flow. I highly doubt any substantial fumes get into the vac and defiantly no fluid is getting there.

But I agree vacuuming up flammable materials with a shop vac is a horrible idea.

[TS Flightlines]

Hey Justin---there is a 1/8 NPT plug on the pump. In your case, before you rotate the pump, put this plug "up" remove it and prime the pump with alittle fuel. Once the pump has primed, you can remount it in the saddles.

Tom

[rv7charlie]

Suggest looking up the specs on the pump cores used in these injection boost pumps. Ex: the Walbro GSL393, used in a couple of models, is rated at 50" (4 feet!) of H2O lift. The other cores have similar ratings; they're positive displacement pumps. If you give the air some place to go other than back to the pump inlet, I'll bet the pump will hose you with fuel before you can re-close the fitting.

[ReidVaitor]

when you say- I replaced the fitting, connected everything back up and tried to start it.... no joy.
What didnt start the engine or the fuel pump? I just completely cleaned out the fuel filter and reassembled it, I too had a loose AN connection, but that never stopped anything. Fuel pressure and flow started right away with no fuel in system.
If the fuel pump is not starting? check your ground connection. I had this issue causing the fuel pump to work intermittently.
If this happens again, I suggest you call Airflow; you may have an actual issue with the pump.