A tale of two fuel lines

[yarcraft91]

I have two boats at the cottage- a 2001 pontoon/50 Merc 2-stroke and a 2006 side-console fishing boat/50 Merc 4-stroke,each purchased new. Inspired by stories here and elsewhere, I decided it was time to replace the original grey fuel lines on each.

Fortunately, I did the 2006 boat first. The old fuel line had no printing visible in daylight, had stiffened a bit since it was new but was still flexible, was significantly dis-colored except where not exposed to fuel (dry side of the fuel tank clamp). FWIW, this hose is under a boat cover or in a building unless I'm running the boat. When I removed one of the hose clamps, I found red printing underneath the clamp, not enough to identify the brand, but it came installed on the new Quicksilver fuel tank sold with the boat. The internal condition of that old hose was terrible- see photos, in which the 2006 hose is always the upper hose. The camera flash did make some of the printing on the 2006 visible, indicating this is a type-B1 hose (see left end of old hose).

The 2001 boat fuel hose had clearly visible red printing identifying it as Mercury Marine B1 hose, was much more flexible than the other old hose, was scarcely discolored. This hose hangs out the back of the pontoon boat all summer. If I had changed this hose first, I might not have bothered changing the other one- which would have been a mistake.

I replaced both hoses with new Mercury-brand B1-15 fuel hose.

Then, I cut the old hoses apart and looked at the condition of the liner, which some of you have reported falls apart after a few years. The two old hoses could not have been more different inside. In the photo below, the 2006 hose is the upper one in each photo, the lower hose is the new B1-15 hose. You can see on the fresh-cut ends that the 2006 hose liner has failed. You can clearly see what the liner should look like in the new B1-15 hose. I didn't bother photographing the 2001 hose because it looks like the new B1-15 on the inside, except that the liner has yellowed somewhat.

I fill the fuel tanks on each boat from the same fuel cans, with the same gas treatments. They sit on opposite sides of the same dock each summer season. So, it's fair to say some old grey hoses are really different than others. In my case, the newer 2006 hose carried an SAE rating (number illegible), while the 2001 hose did not but did carry an ISO number. Based on my experience, if I came across a grey fuel hose that had stiffened a bit, discolored and the printing had disappeared, I'd replace it immediately. If it doesn't show those signs, it may be just fine. YMMV.

[THROWINWOOD]

Caught your post on THT , checked my 07 grey kicker hose and sure enough the liner was in a million pieces , some in the hose and some in the filter ahead of the fuel pump.

All fixed now ,new hose new filter , system cleaned

Thanks for the heads up on this problem

Dave