Fuel line material?

[amuller]

I’m getting ready to reinstall a build-in bow fuel tank in my Crestliner. (Mainly to improve weight distribution and declutter the cockpit.) This will involve maybe 17 feet of line. I hesitate to use all rubber hose as there are too many problems with deterioration. Copper does not seem appropriate in the bilge of an aluminum hull. I suppose that leaves aluminum tube, or nylon, or possibly teflon (PTFE). Anyone have an opinion?

[billw]

Short answer: USCG Type A1. This hose will outlast you and I.

Long answer:
https://www.uscgboating.org/assets/1/AssetManager/ABYC.1002.01.pdf

Long live American manufacturing!

[amuller]

Yes, I found that publication after posting. “United States Coast Guard and Environmental Protection Agency
Compliance Guideline How to Comply with the Law-Fuel and Emissions
© 2011 American Boat & Yacht Council, Inc., 2011.

It’s quite comprehensive. Not all applies to outboards.

Aluminum fuel lines are prohibited: (Not sure of the reasons.)

“If metal is used for any portion of the fuel line (except for fittings) from the tank connection to the engine connection (usually at the fuel pump), the metallic fuel line portions must be seamless, annealed:
(1) Copper;
(2) Nickel copper (Monel); or
(3) Copper-nickel.
No other metals are permitted.
Also, the thickness of the tubing wall must be at least 0.029 inches unless the fuel line portion is a corrugated or accordion type of flexible fuel line. Tubing is available with thinner wall thicknesses, but they SHALL NOT be used.”

Expect I will use the A1 hose, as I can snake it trough the bilge. To do a good job with metal line would have to take up the flooring and clamp at every frame….

[rudderless]

I’ve been using pex heating tubing for 5 years now to run about 12′ from front to back. Absolutely no issues at all. I used the heating tubing as it is oxygen barrier tubing and might be like the gas tanks being low permeability .

…and most importantly its red…
…uses approved clamps…
…3/8 rubber hose fits perfectly over the 1/2 pex fittings and can accept the pex plamps for a clean look…

• This reply was modified 4 years, 6 months ago by rudderless.
• This reply was modified 4 years, 6 months ago by rudderless.

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amuller

[amuller]

Very interesting idea! The pex tubing should be just as inert to fuel as poly tanks, and is quite sturdy. The only downside I can think of is that pex is not at all sunlight resistant and would need to be covered in exposed places. What diameter did you use and what sort of fittings? Did you use the pex-al-pex stuff or the regular barrier tubing? I’m going to explore this……

Of course surveyors, Coast Guard Aux. and such might have a fit?

Alan

[rudderless]

Since I’m a plumber for 40 years I have this stuff laying around. I used 1/2 pex with crimp brass fittings available from your friendly plumbing supply place. My tubing has been in the sun for 5 years with no degradation. I have used the pex ball valves and the teflon seals have been holding up for just as long with gas exposure. Just plain barrier heating tubing…no al in it.

[amuller]

Not a plumber here for sure but have repiped a couple of houses with PEX and experience has been good. And cost of material is diddly compared to anything sold as “marine.”

[rudderless]

If only life was about facts. So many things have other factors that are not about technical aspects. Pex was kept out of the US for many years as it is much less expensive and took a lot of the plumber out of the plumber…

[amuller]

I looked and have PEX in 1/2, 3/8, and 1/4. I don’t think proper insert fittings and crimp rings are made for 1/4″ pex, or if they are I haven’t seen them. But fittings used with 1/4″ hose would likely work. There’s no real pressure involved.

[rudderless]

If ya gotta go 17′ use the 1/2 heating pex..5/8od. 1/4″ for 17′ seems rather small….

[Author]

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