Fuel Fill Hose Cracking

[kdaniel3]

Had my gasoline fill hoses replaced last week due to some noted cracking where they attach to the top of the fuel tanks. Once they got the hoses out, there were long cracks, hose had expanded, and was very stiff. 13 years was too long for these hoses and I believe the manual recommends an inspection and replacement schedule much shorter than that.

This was out of a recently acquired 2004 Carver 396MY and the hose had a 2003 manufacture date, see attached pics.

[dsolo]

Is the hose condition related to over filling the tank? Or fuel tank vent lines being plugged? Trying to understand how a hose rated to withstand fuel contact can degrade?

[bud37]

Is the hose condition related to over filling the tank? Or fuel tank vent lines being plugged? Trying to understand how a hose rated to withstand fuel contact can degrade?

Just the nature of rubber hose...I bet you could take a new piece of that hose and put it in your living room and in 15 years it will have dried out.Now engine compartment ,hot cold cycles and fuel vapour , well you get the idea.I believe the rating would be for a set period of time to handle fuel. I have pulled that stuff out of a couple boats and it is always degraded more than it looks on the outside..... :beer good:

I have some left over( still in plastic ) from last boat and will replace the hose an this boat when I can get my old body down there..

[tomschauer]

Yep, rubber hose has a limited lifetime. Most surveyors will tell you to check it every year for cracks and replace it after ten years of service even if no cracks are present. I doubt ethanol adds to the life either.

[dsolo]

Looks like another project over the winter. I am sure you are talking about both the fill and feed hose lines? My 1997 405 must be a candidate for the change. Any pointers or recommendations?

[Viper]

UV affects the longevity of the rubber. When you purchase any rubber product like hose, impellers, etc., plan ahead and have them specifically order in what you need rather than ending up with product that may have been sitting on their shelf under UV emitting florescent lighting for years.

At minimum, you should get a quality Type A-2 marine fuel hose which is rated for diesel and E15 gasoline. Don't forget to replace the vent hose as well, and make sure it is looped upward from the hull vent before it heads to your tank. From the hull vent fitting to the tank should be down hill only with no sags in the hose where fuel would sit in an over-fill condition and prevent venting. Use stainless steel clamps only. Premium clamp designs help seal better than the typical hose clamps. Double clamping while not a requirement, also contributes to a tighter/better seal as you won't find out if the connections are secure enough to prevent leaks until you're over-filled one day. A poor seal may leak during the fill process so check for leaks at your first fill after the install, and use your nose to help.

The supply lines to the engines will have a hard inner liner and you should avoid using a heat gun to help with installation as that might distort and tear the liner at the connection which would de-rate the hose. I've also seen the liner get heated up enough that it separates from the outer cover and gets pushed into the hose during installation causing a restriction.