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New fuel line - solid to braided
Posted: August 14th, 2022, 6:09 pm
by DoubleTrouble71
Hi all,
I had to replace a fuel pump on my 454XLs and during that change the solid fuel line from the fuel filter to the fuel pump must have flexed and developed a hairline crack where the steel rolled together. That part for my 1994 motor is no longer available. So I went to a hose fabricator joint and they made one out of braided stainless. I put it on, checked and ran the motors with no leaks or issues that I could tell. Anyone have any gotchas to watch out for? I plan on replacing the other one on the starboard engine too has I suspect it may have a similar condition or could soon.
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Re: New fuel line - solid to braided
Posted: August 14th, 2022, 9:23 pm
by bud37
Well since you asked.....unless something has changed recently ( and maybe it has ) I don't believe that braided hose is USCG approved for fuel line use. You can check the regs to be safe, I used lots on race cars over the years but I think the sticky point other than the regs requiring approved hose would be inspections and the big one...insurance, what does your policy say?
Hopefully there has been an update...
Re: New fuel line - solid to braided
Posted: August 15th, 2022, 11:08 am
by DoubleTrouble71
Well, looking at the coast guard regs here's what it says:
IT’S THE LAW - USCG:
183.538 Metallic fuel line materials.
Each metallic fuel line connecting the fuel tank with the fuel inlet connection on the
engine must:
(a) be made of seamless annealed copper, nickel copper, or copper nickel; and
(b) except for corrugated flexible fuel line, have a minimum wall thickness of 0.029
inches.
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.
Metal fuel lines used on the engine, i.e. the fuel line from the fuel pump to the carburetor, may be
made of materials other than those listed. This line is usually supplied with the engine.
So, given this is on the engine, I wonder if I can interpret it be ok to be made of other material. The one I replaced is from the fuel filter to the fuel pump.
Funny that it says it must be seamless and I'm pretty sure the old line was made from some type of rolled metal that technically has a seam. Maybe I'm wrong about that.
Re: New fuel line - solid to braided
Posted: August 15th, 2022, 11:15 am
by km1125
I wouldn't think it would be under "metallic fuel line materials" section, as the flexible hose is really a rubber-based hose just reinforced with the stainless mesh cover.
But (and it's been a while since I read through them), I think there is also a part under the flexible lines section that excludes the lines on the engine.
Re: New fuel line - solid to braided
Posted: August 15th, 2022, 11:59 am
by bud37
DoubleTrouble71 wrote:Source of the post So, given this is on the engine, I wonder if I can interpret it be ok to be made of other material. The one I replaced is from the fuel filter to the fuel pump.
Personally I like braided but I believe the fittings may be where the problem lies unless there is some approved hose with a stamp out there now.
The issue is not how we interpret the regs but how the guy that jumps on board to inspect, or the insurance company interprets. It says you can use other materials.....well there is approved rubber hose that is stamped as such.......there is also an approved method of joining the much thicker fire rated hose to a metal line ( it involves a certain type of flare ). The thicker hose is tricky to get clamped right so be aware if you go this way.
It is tough to pick thru but good on you for asking and finding part of the reg that applies to your question.It is good to revisit these things every now and again......

Re: New fuel line - solid to braided
Posted: August 15th, 2022, 12:55 pm
by Viper
The surveyors I know do not like braided line in the fuel system as there is no way to confirm whether the hose inside conforms to marine fuel line regs. It could be anything in there, like heater or general purpose hose. It usually results in a red flag on the survey.
Re: New fuel line - solid to braided
Posted: August 15th, 2022, 11:51 pm
by DoubleTrouble71
Yeah,I agree I can't see what's in there. Although, in my defense, the place I went to I specifically informed them it was for fuel lines AND they do a lot of racing hoses there as well. I suppose I'll find a better alternative just to be safe but for now feel pretty safe using the boat until I can get yet another set of replacements.
If anyone knows where to get OEM replacements for the 454XL lines I'd appreciate it. I don't see anyone onlne with anything in stock so I think I will have to go to a hose versus a solid line that was the OEM.
Re: New fuel line - solid to braided
Posted: August 16th, 2022, 7:02 am
by Midnightsun
Keep the old units as they will be needed to fabricate new to the same configuration. I must assume they do not want steel to prevent an accidental spark when removing or installing being there will be gas/fumes present. Pretty sure any good hydraulics shop can custom bend and flare with the appropriate fittings. We bend and flare all the time in our shop for our hydraulic pumps however usually JIC thread and stainless steel tube.
Re: New fuel line - solid to braided
Posted: August 16th, 2022, 4:37 pm
by Viper
I make my own. It's not that difficult. A good tube bender and flaring tool, a couple of fittings, and some practice is all it takes.
Re: New fuel line - solid to braided
Posted: August 16th, 2022, 4:45 pm
by Midnightsun
Viper wrote:Source of the post I make my own. It's not that difficult. A good tube bender and flaring tool, a couple of fittings, and some practice is all it takes.
Exactly. No rocket science or special education required.

Hardest part is locating the material required.