I replaced the fuel line on my 50HP Merc just a few years ago and the inner liner is collapsing already. I have ran alcohol free gas and the boat is stored in the garage so can't blame UV for the problem. I think I am going to buy automotive fuel line and cover the line with cable sleeving to minimize UV damage.
Thoughts.
https://www.amazon.com/225FWY-Expandable-Sleeving-Sheathing-Braided/dp/B07121CVYB/ref=sr_1_13_sspa?keywords=5%2F16%2Bplastic%2Btubing&qid=1567090213&s=sporting-goods&sr=1-13-spons&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUEyWlhOTTM2TFZHRVY0JmVuY3J5cHRlZElkPUEwMDc0OTQwM1FBUlRLREVTNTZWUCZlbmNyeXB0ZWRBZElkPUEwNDkyNTU2MU5QVk45REpCRlcxJndpZGdldE5hbWU9c3BfbXRmJmFjdGlvbj1jbGlja1JlZGlyZWN0JmRvTm90TG9nQ2xpY2s9dHJ1ZQ&th=1