I see that lined EPA compatible fuel lines on lawn mowers too....liner bunches up, falls apart, etc. Good thing is that it generally won't hurt a 4 stroke and certainly not a lawn mower, just makes the owner mad when it quits under a load.
Yamaha fuel line is the only one worth having...down side is that it kinks easier than Gates 3/8 fuel/emissions hose does. And it's expensive. Not a big deal. Just keep it routed in a way that it aint' gonna kink if the tank slides over or something. I have plenty of Gates hose, and it's not stellar, good stuff but not great. UV resistant it is not...
outta see the duck hunters/2 stroke boat racers. Put $5000 worth of mods into the motor and the setup (jack plates, etc) and use a $25 fuel line, it does it's thing and destroys the motor. Big deal right? Then they'll be online looking for another 3 cylinder to mod, do the same thing, burn it up too. Unreal. The other end is the bass boat guys, 150+ HP 2 stroke, fuel line collapses, burns a cylinder down. Those powerheads are NOT cheap to rebuild. Some of them are $3000+, just for rebuild.
Couple years ago we fished the salt and the guy's boat was a 26' sea hunt, 300hp Yamaha 4 stroke. We're about 12 miles offshore, mostly full throttle, I turned around and looked back and noticed that the primer bulb was sucked completely FLAT. Restriction somewhere on the suction side, be it the tank or whatever. I showed it to the guy who was fishing with me and he puckered up....remember...he's real skittish of the big water anyway. After we stopped, my friend mentioned it to the captain/boat owner and he said he'd had it die once or twice and couldn't find the issue. I asked him where the fuel tank filler was, he pointed it out, I pulled the fill cap off and the vacuum was horrible. Vent plugged. Told him to find the vent hose when he gets a chance and push the dirt dobber nest out....guy called me a couple days later and said man how'd you know it was a dirt dobber. Good guess I reckon.
