Speaking of fuel lines, I have seen some bizarre things happen with them in the past.

One person bought a few feet of silicone tubing and ran lengths of it to their engine in the airplane like you would expect. But the engine would not draw fuel or run. Eventually we found that the inside hole was missing on the piece inside the fuel tank Apparently it was a solid plug of tubing right there. You had to really look, it was hard to even see it. I remember someone else running into that problem here on the forum a while back too. So do try to see if the inner tube is clear in your tubing before you go to use it. You never know if some debris gets inside as well.

Another time was a piece of inside fuel tubing sloughed off the inner wall forming a one way valve. You could add fuel, but you couldn't get it back out. Then once there was a piece sloughing off the inner wall that plugged up the fuel inlet fitting on the engine.

Years ago at the hobby shop, I caught a kid poking pinholes in the roll of new fuel tubing with a needle. The owner was upset and the parent more or less took off with the bratty kid. I was hoping the parent would own up to it and buy the ruined roll of tubing but he took off before the owner could get him to pay for it. The owner took all of the rolls of fuel tubing off the wall as he didn't know how much damage the kid did or for how long.

So you never know, even that piece of new tubing you just bought could be bad.