[JAG]

To check my fuel vent and vent valve, I have a 6ft piece of surgical tubing and a glass of water (or Costco bottle of water). I put the surgical tubing over the vent line on the trailing edge vent line at the wing tip. Next, I take a deep breath and blow into the other end of the tubing. If the air goes into the tanks (no resistance to my blowing), I know the vent is clear to the tank. Now, the next step I cheat a little...I take my compressor nozzle, and give a short shot into the tubing (simulating a real deep breath - I do this so I don't pass out), which slightly pressurizes your fuel tanks, then stick the end of the hose into the glass of water or bottle, and see if it bubbles. If it does, you know the vent valve weep hole is also doing its job of releasing pressure as well. if you have a fuel cap that does not seal well, your breath alone may not be enough to pressurize the tank (found that out the first time).

The main thing I am concerned with is the first part of the test - ensuring good flow of air into the tank. Small bugs can tend to block this line and that can cause issues with fuel flow or worse, collapsed tank.

Jeff