Deteriorating fuel lines

I was having the steering cylinder rebuilt on my boat. I hadn’t changed the fuel filters in a couple of years so I asked them to do that also. The filter on the motor was full of crap from the fuel lines breaking down. They cut open one line for me and there was both scales and grains of stuff on the inside of the lines. 90% of the gas it’s burned was non-ox premium so it’s not from ethanol. The boat is 13 years old so it’s not a total shock but I had never seen much in the filter the times I had changed it and I thought the oxigenated fuel was what wrecked fuel lines.

Is it a Mercury fuel line? They had some bad ones a while back. The interior breaks down and causes problems.

Yep water in fuel with ethanol in it is what wrecks fuel lines if allowed to sit for a few months. I am guessing you had ethanol from some source at some point.

Check this out for good ol redneck proof that ethanol is wicked stuff.

Netguy wrote:

Is it a Mercury fuel line? They had some bad ones a while back. The interior breaks down and causes problems.

Yamaha lines

Pat K wrote:

The filter on the motor was full of crap from the fuel lines breaking down. They cut open one line for me and there was both scales and grains of stuff on the inside of the lines. 90% of the gas it’s burned was non-ox premium so it’s not from ethanol. The boat is 13 years old so it’s not a total shock but I had never seen much in the filter the times I had changed it and I thought the oxigenated fuel was what wrecked fuel lines.

At 13 years old, IMO the issue is more just plain old age than anything. Fuel lines never did last forever, even before ethanol was a thing I can remember working on engines where the float bowl was full of “rubber dust” from degraded fuel lines. Given all the things a fuel line needs to be, it’s not surprising to me that they would wear out after over a decade in service.

Write the date on the new lines with a paint marker along with “replace in 10 years” and then you’ll know when to do it again next time so you get them before they start to fail.