3/8 fuel line keeps splitting on me, and I think I found the real culprit at my bench
I went through 4 feet of 3/8 fuel line in two weeks before I noticed the pattern: every split happened within an inch of the same flare fitting. Turned out my tubing cutter wheel was dull enough to leave a tiny burr that nicked the hose from the inside, and a burr I couldn't even feel with a fingernail was enough to do it. Grabbed a fresh wheel from NAPA on 5th and the problem quit cold. Anyone else got a go-to check for hidden burrs before the hose goes on?
A dull wheel will get you every time. I run a Q-tip around the flare after cutting, the cotton snags on anything my finger can't feel. Cheap trick but it saves a lot of hose.