diesel fuel lines

are there any preferences for the type of material that diesel fuel lines should be made of? I presently have copper tubing but it looks very dirty - accumulations of crud on the bottom. If I replace the fuel lines, should I replace with copper tubing or the appropriate fuel hose?

following

either are satisfactory.

where and how they are installed makes a world of difference.

I chose USCG approved rubber fuel line approved for diesel fuel during my refit (replace all as it was 14 years old). In the event that I own the boat 15 years from now, I'll replace it again. Once you switch to rubber hose, if you ever have to replace it again, cost and time involved will be very minimal. I have seen copper lines for steering fail, presumably from vibration. No way to know the condition until they fail. With hose you can visually check for cracks and flex it to see how brittle it's getting.

Ted

Are you wanting to go back with hard line or flexible hose.?

If I can use either tubing or hose, I think I will go with hose. The installation will be easier and I think the costs are a push. Thanks for your advice.

Use the proper approved rubber hose.

Clean,bright-colored rubber hose looks pretty but takes up more space & has much less of a bend radius than copper. Done in a neat fashion ,copper looks nice in the engine room,too. I would have to imagine copper has less fuel flow restriction verses rubber-walled hose. That said, I'll make due with the 5/16" supply & return lines in our boat and if ,in the future,we need/decide to repower & the engine manufacturer calls for larger diameter lines, I'm sure it will be hose with which the lines get replaced.

Have used both , rubber is easier and quicker.

Purchase the screw on fittings , rather than the store sweged on and you can make repairs easily.

That said on building a new boat I would use either steel tubing or small diameter steel pipe , mount it , paint it and forget it.

O C Diver said:

I chose USCG approved rubber fuel line approved for diesel fuel during my refit (replace all as it was 14 years old). In the event that I own the boat 15 years from now, I'll replace it again. Once you switch to rubber hose, if you ever have to replace it again, cost and time involved will be very minimal. I have seen copper lines for steering fail, presumably from vibration. No way to know the condition until they fail. With hose you can visually check for cracks and flex it to see how brittle it's getting.

Ted

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Ted, do you happen to have any pix of your fuel lines you could post? I’m especially interested in how hoses look coming off a fuel distribution manifold.

Like many here, I suspect, I have 30-year-old copper lines. Lots of tight bends particularly off the manifold. I need to replace one from the polisher that is badly crimped and I have my doubts about a few others.

FF said:

Have used both , rubber is easier and quicker.

Purchase the screw on fittings , rather than the store sweged on and you can make repairs easily.

That said on building a new boat I would use either steel tubing or small diameter steel pipe , mount it , paint it and forget it.

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Fred, do you have a link or photo of the screw-ons you’re suggesting?

angus99 said:

Ted, do you happen to have any pix of your fuel lines you could post? I’m especially interested in how hoses look coming off a fuel distribution manifold.

Like many here, I suspect, I have 30-year-old copper lines. Lots of tight bends particularly off the manifold. I need to replace one from the polisher that is badly crimped and I have my doubts about a few others.



Fred, do you have a link or photo of the screw-ons you’re suggesting?

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Fred may be talking about screw on reusable fittings and hose for fuel line, like the kind for hydraulic.

Pack Mule said:

Fred may be talking about screw on reusable fittings and hose for fuel line, like the kind for hydraulic.

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Thanks, Marty. I’ll look them up. Just not clear on how they connect to the hose without swaging.

angus99 said:

Thanks, Marty. I’ll look them up. Just not clear on how they connect to the hose without swaging.

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they screw on ...there is a fitting that goes inside the hose, and the outer fitting scews on and compresses everything. no swagong necessary and they are reusable.

an alternative is the press to fit> Parker blue hose and use a hose clamp yo met ABYC.

angus99 said:

Ted, do you happen to have any pix of your fuel lines you could post? I’m especially interested in how hoses look coming off a fuel distribution manifold.

Like many here, I suspect, I have 30-year-old copper lines. Lots of tight bends particularly off the manifold. I need to replace one from the polisher that is badly crimped and I have my doubts about a few others.

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All hose clamps are stepless (lined) so the worm and slots don't come in contact with the hose. All hangers are lined or plastic. PVC electrical conduit hangers come in many sizes, are inexpensive, and work great for hose and electrical wiring.





Ted

Thank you both!

Parker 221FR hose is the blue hose typically used in marine fuel applications. It is expensive. It has the USCG A1 embossed on the outer jacket. Any hose you use for fuel must carry that A1 USCG rating, a surveyor can ding you if it's not A1.


The fittings other posts have described are series 20. They are field attachable, two piece. If you read the fine print, 221FR hose is supposed to use series 26 fittings (require a hydraulic crimp) to fully meet the A1 spec, but I've never heard of a surveyor calling that out. The series 20 fittings are commonly used, they are easy to make up with a vise and wrenches. The hose can be cut with a cutoff wheel, hacksaw works but makes a messy cut.

Keep in mind that anything supported over an engine must be a metallic support, in a fire it won't let go. So the best way to fasten the hose is the rubber lined stainless pipe band.

Another option, similar to the Parker 221FR hose is Aeroquip FC234.

One important no no is galvinized, the diesel melts the galv and clogs the injection pump, injectors....

In Europe diesel fuel lines must be double clamped (AND OPPOSITE) on each side. Does this obligation not apply in the US?

Fred may be talking about screw on reusable fittings and hose for fuel line, like the kind for hydraulic.

When you visit the store to buy the hose , they will happily provide either crimp on or screw on fittings.

O C Diver said:

All hose clamps are stepless (lined) so the worm and slots don't come in contact with the hose. All hangers are lined or plastic. PVC electrical conduit hangers come in many sizes, are inexpensive, and work great for hose and electrical wiring.

View attachment 72743

View attachment 72744

Ted

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As a side note... What a lovely fuel rig. Simple and neat.

Airstream345 said:

following

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For the record: You can subscribe to a thread without having to post in the thread itself if you like. At the top of the page under 'Thread Tools' there is a drop-down menu where you can select 'Subscribe to this thread'

Just a quick FYI

Mr. Blu said:

In Europe diesel fuel lines must be double clamped (AND OPPOSITE) on each side. Does this obligation not apply in the US?

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Don't believe it applies in the USA. Certainly nothing wrong with it, but not really necessary on the vacuum side. Pressure side probably doesn't see 3 psi. Obviously everything that sees elevated fuel pressures on the engine is metal tubing.

Ted

Tom.B said:

As a side note... What a lovely fuel rig. Simple and neat.

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Thanks!

This is what the boat came with:







Pretty easy to improve on this Rube Goldberg setup.

Ted

Rubber hose tends to look crappy ( as does some wiring) because it sags between support points.

A piece of dowel next to the hose , and wire ties can make a big difference.

I was referring to the pictures of OC Diver, where just are single clamps on all the fuel lines.

2 are probably overkill.

A study or 2 showed very little benefit from a second clamp unless the first was crap or installed poorly.

Why not use 316 stainless tubing and fittings?
We use it at work for all sorts of things.
You can get a 20' joint for about $35 and the fittings are about 10 each.
It is not hard to bend. I think it would be a lifetime fix and it would look good.

latravcha said:

Why not use 316 stainless tubing and fittings?
We use it at work for all sorts of things.
You can get a 20' joint for about $35 and the fittings are about 10 each.
It is not hard to bend. I think it would be a lifetime fix and it would look good.
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View attachment 72785

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Stainless is good for dairy products but a no-no in the engine room regarding fuel supply & transfer. Get ready for a severe scolding Latracha!

I’ve long been an Aeroquip fan. Easy to make up even in the worst condition. Of note, you must have Aeroquip assembly lube.