TOPIC: Impermeable fuel lines (long)

Found out a funny thing about the modern "impermeable" marine fuel lines. If you folks already knew this, pardon the wordy post.

I ordered a replacement Moeller fuel line setup including squeeze ball, line size 3/8".

My old line was 3/8 but the brass fitting in the motorwell reduced the tank line size from 3/8" (tank side) to 5/16" (motor side). I didn't want to crank down on the new 3/8" line to make it seal to the 5/16 fitting, like the prior installer did. So I ordered a new fitting, 3/8 to 3/8.

Installed the fitting, and found the new Moeller line has an impermeable inner liner made of tough, clear, non stretchy material. It is not bonded to the outer flex hose. All attempts to slide my fuel line onto the brass nipple resulted in the inner liner crinkling up inside the outer hose, creating a serious fuel blockage. After an hour or so I ended up putting the old 5/16 brass fitting back in and double clamping and cranking down hard on my new 3/8" line. If there's a trick to sliding a Moeller 3/8" fuel line onto a 3/8" brass nipple, I couldn't find it. The liner won't stretch and adding lubricant didn't help either.

If anyone's having fuel starvation problems after using this kind of fuel line on a brass nipple fitting, you might pull it off and look inside to see if the liner is crinkled up in there, blocking fuel flow.
In the photos you can see the inner liner. It pulled right out with tweezers.

The Moeller stuff is junk. I quit using Moeller years ago and buy strictly BRP.

I had a serious fuel starvation problem with the lined fuel line. I found the problem one day shut down on the lake and pulled the whole liner out with one tug. It looked like Saran warp. Problem solved. I replaced with NAPA non lined fuel line.

Interesting! Screw the new stuff, stick with regular gas hose for sure. Damn EPA saving us is killing us!

One thing you could had done is take the fitting to a belt sander and sand down most the barb that end, just leave a little left. Its not under a ton of pressure so damn sure aint gonna blow off. Clamp and forget after a good tug it to make sure.

I was having problems with my 2003 Honda with the new gas. Small black particles all through the carb even with gas filter. Out of desperation I cut the fuel bulb on it that came with the engine and the inside left a black residue on my fingers. Never assume newer is even good enough for new fuel. Try this. pure-gas.org/

I thought about grinding off a little of the barb, but decided it was running well through the old 5/16 fitting, so I just put that one back on. Oh well, serves me right for trying to do things the right way! If I hadn't pulled that line back off to check it, I would have had a real blockage problem next time out.

My son's boat had an EPA compliant (auto venting) fuel cap on a 6 gallon tank. It was amazing. In the hot sun, the tank expanded til you thought it would explode. With the motor running, it wouldn't auto-vent and the motor would die. Somebody save us from all this protection!

Robby321 wrote:

Interesting! Screw the new stuff, stick with regular gas hose for sure. Damn EPA saving us is killing us!

One thing you could had done is take the fitting to a belt sander and sand down most the barb that end, just leave a little left. Its not under a ton of pressure so damn sure aint gonna blow off. Clamp and forget after a good tug it to make sure.

FWIW, when I fit a fuel line on the brass coupler that's a little snug I warm the line up with a heat gun so it's stretchy, slide the line on and tighten the clamp while it's still warm. Newer fuel lines are a clear/blue tint material that won't be affected by ethanol or other additives but they do kink easily.
Cal

The problem I have is the new fuel lines(grey plastic looking line) crack after one year. The old lines lasted for at least 5 yrs.

I hear ya. I consider that fuel lines are something that need regular checking and replacement. Problems arise? Just change it. I prefer the visible lines. They have a tendency to stiffing up after two years but you can see your fuel in the line and if there is a problem like an air leak you can get a heads up.

Norm - did you try smearing a film of dish soap on the barb 1st? Soap often works when nothing else will.

Yup, tried dish soap and silicone grease but the problem is, that inner liner has no stretch at all and it's not bonded to the outer hose, so any pressure when installing and it just slides in and wads up inside the line. Seems to be sealing OK on the smaller 5/16 fitting, and next time it needs replacing I'll go with good quality automotive fuel line, or look for the BRP brand that jimandros mentioned. Since the law required this non-permeable stuff beginning around 2011, I think our boats generally would be exempt or grandfathered in.