This is something I know I've read about before on these forums, nonetheless I ended up with a problem that others have warned about, so I'm posting this as a reminder to whoever might want to avoid the issue.
I flew my plane for the first time two weeks ago. Today I made my 6th flight and have 9.9 total hours on it. The first three flights were with lower fuel levels and were short flights, mostly about an hour. I noticed at the time that my fuel pressure using just the mechanical fuel pump on the engine seemed at the low side of normal. I didn't really isolate that to one tank or the other at the time but in thinking about it since I believe I could have.
The last three flights I made with full tanks, but used the left tank primarily just to even up the weight balance, then switching to the right tank prior to landing. Today I decided to fly on the right tank for about an hour and a half and switched to the left for landing. While I was flying, I noticed my fuel pressure was on the very low end of normal toward the end of the flight. After landing and getting out of the cockpit to put the plane away I noticed the right tank was really oil canned. I quickly pulled the fuel cap and a big sucking sound was made and the tank returned to normal. It hit me right then that I must not have a good vent. I went to the bottom of the fuselage where my vent lines come out and sucked on the vent with my mouth. No joy. The left tank vent I could move air. So, a blocked vent was confirmed.
I removed the vent line at the right tank and discovered that the line from the fuselage up to the tank was able to move air. I hooked a hose onto the fuel tank vent nipple and blew as hard as I could but could not move any air. So the blockage was in the tank vent line somewhere. I was praying by that point that I wouldn't have to remove the tank and get in there. So I decided to snake some safety wire through the line starting at the wing root and see if I could open up the blockage. Fortunately after a few tries I was able to punch through the blockage and it fell down into my mostly empty tank. It appeared to be an insect of some kind and some other gunk. I was then able to blow through the vent line. I reconnected everything and confirmed good venting throughout.
After I built my tank and pressure tested it I sealed up all orifices and left the fuel cap on the entire time of the build until final connection. There was no way that blockage happened with the tank sealed up like that. So, the only way it could have happened is I installed the line with the blockage ALREADY IN IT! What a moron...please do not follow my example and please check that your tubing is clear BEFORE you permanently install it. I'm expecting that the fuel pressure on the mechanical pump will be in the higher end of normal now. I feel like I dodged a bullet...
I flew my plane for the first time two weeks ago. Today I made my 6th flight and have 9.9 total hours on it. The first three flights were with lower fuel levels and were short flights, mostly about an hour. I noticed at the time that my fuel pressure using just the mechanical fuel pump on the engine seemed at the low side of normal. I didn't really isolate that to one tank or the other at the time but in thinking about it since I believe I could have.
The last three flights I made with full tanks, but used the left tank primarily just to even up the weight balance, then switching to the right tank prior to landing. Today I decided to fly on the right tank for about an hour and a half and switched to the left for landing. While I was flying, I noticed my fuel pressure was on the very low end of normal toward the end of the flight. After landing and getting out of the cockpit to put the plane away I noticed the right tank was really oil canned. I quickly pulled the fuel cap and a big sucking sound was made and the tank returned to normal. It hit me right then that I must not have a good vent. I went to the bottom of the fuselage where my vent lines come out and sucked on the vent with my mouth. No joy. The left tank vent I could move air. So, a blocked vent was confirmed.
I removed the vent line at the right tank and discovered that the line from the fuselage up to the tank was able to move air. I hooked a hose onto the fuel tank vent nipple and blew as hard as I could but could not move any air. So the blockage was in the tank vent line somewhere. I was praying by that point that I wouldn't have to remove the tank and get in there. So I decided to snake some safety wire through the line starting at the wing root and see if I could open up the blockage. Fortunately after a few tries I was able to punch through the blockage and it fell down into my mostly empty tank. It appeared to be an insect of some kind and some other gunk. I was then able to blow through the vent line. I reconnected everything and confirmed good venting throughout.
After I built my tank and pressure tested it I sealed up all orifices and left the fuel cap on the entire time of the build until final connection. There was no way that blockage happened with the tank sealed up like that. So, the only way it could have happened is I installed the line with the blockage ALREADY IN IT! What a moron...please do not follow my example and please check that your tubing is clear BEFORE you permanently install it. I'm expecting that the fuel pressure on the mechanical pump will be in the higher end of normal now. I feel like I dodged a bullet...
