Best choice for Gas line

[outofthenorm]

I'm in the process of overhauling my gas engine installation. The fuel lines are all 1/4 in soft copper tubing with brass end fittings. It has never leaked, but it's all more than 30 years old. If I replace it, is copper still a good choice, or is there a better way now?

- Norm

[pcford]

Neoprene..the rubbery tubing. Get CG approved.

[Jim Ledger]

PC, what do you use for fittings? Hose clamps and barbed brass? Or is there a way to transition to flare and tubing?

[djn]

Hi Jim, hose clamps and barbed brass is far superion to flare fittings in this situation. It is all low pressure and can move with the slight movements of the engine. A tube and flare, being stiff, can fatique and crack over time with movements you can not detect with your own eye. Cheers.

[pcford]

Hi Jim, hose clamps and barbed brass is far superion to flare fittings in this situation. It is all low pressure and can move with the slight movements of the engine. A tube and flare, being stiff, can fatique and crack over time with movements you can not detect with your own eye. Cheers.

Yup.

[sdowney717]

http://findarticles.com/p/articles/mi_m0BQK/is_3_9/ai_n6040504

Every flexible hose should be clearly marked U.S.C.G. If not, replace it immediately.

Or I suppose if the CG sees it is not CG approved, they could fine you and perhaps force you to be towed back to port.

[Peter Malcolm Jardine]

Most hoses are clearly bought with the fuel rating right on them Norm... I use hose with barbed transitions...replaced all mine too... the modern rubber fuel hose is very very tough.

[soba]

The reason copper is no longer used on engines is because of the vibration. Copper hardens slowly when bent or vibrated and that causes (eventually) a leak. We see it all the time on old engines.

Neoprene fuel hose is best (cheap, too...go to a gates or goodyear rubber products store) but Viton works well, too. I don't recommend stainless unless you have a high pressure fuel application, as it is subject to the same problems as copper except in very short runs or with neoprene hose "isolators."

Also, I recommend the BRASS barbed fittings over stainless barbed fittings. The stainless seems to need more torque to seal properly and we generally prefer not to have fittings break off while installing them or doing maintenance. Pipe iron fittings are good, too, but can be narsty in marine applications.

*stone cold soba*

[outofthenorm]

Thanks all. The engine is a 4-cyl gas with very low fuel pressure. It's used little and runs very smoothly, so I suppose that's why I"ve never had any leaks. But I've got it out on the bench now, so it's easy to change everything. I guess 30 years or so is a long enough life for the old stuff!

Neoprene and brass barbed fittings it is.

- Norm

[Bruce Hooke]

http://findarticles.com/p/articles/mi_m0BQK/is_3_9/ai_n6040504

Every flexible hose should be clearly marked U.S.C.G. If not, replace it immediately.

Or I suppose if the CG sees it is not CG approved, they could fine you and perhaps force you to be towed back to port.

This might be true on an inspected boat (a boat that carries passengers for hire) -- I don't know much about how that world works. However, other than that, I would be surprised if failure to use Coast Guard approved flexible hose for the fuel lines would cause the Coast Guard to fine you and force you to be towed back to port unless there was some other problem going on like a fuel leak, in which case that would be the cause of the citation, not the lack of a Coast Guard stamp on the hose. The article cited does not seem to support the assertion that failure to use Coast Guard approved hose would cause the Coast Guard to fine you and tow you back to port. My experience with the Coast Guard has been that they tend to focus on much more blatant issues. However, I should make it very clear that I am just speaking up because the statement made does not mesh with my past experience with the Coast Guard, but I am IN NO WAY knowledgeable about inboard motor installations.

Using Coast Guard approved hose certainly seems like a good idea...

P.S., it is also worth noting that I suspect sdowney717 is talking about the U.S. Coast Guard, and that is the only Coast Guard I have experience with. I don't know anything about how the Canadian Coast Guard would handle this sort of situation.

[rbgarr]

From ABYC H-24

The United States Coast Guard has promulgated mandatory requirements for gasoline fuel systems in 33 CFR , Subpart J, Sections 183.501 - 183.590. Refer to the CFR for complete, current federal requirements.

[Bruce Hooke]

Here are the detailed regulations:

http://www.uscgboating.org/safety/boatbuilder/downloads/FUELSYSTEM.pdf

I did not realize the detail the regulations go into regarding inboard motor installations. This is certainly rather different from what I have seen as regards other parts of a boat. I would still be surprised if the Coast Guard were to issue a fine and shut down a boat solely because the fuel hoses did not have the proper stamp on them. This level of attention to detail seems like it comes into play more when the boat is being manufactured rather than during on-the-water inspections, but I could be totally wrong! :D

It should also be noted that we are again talking about the U.S. Coast Guard, whereas the question came from Canada.

[Andrew]

From ABYC H-24

The United States Coast Guard has promulgated mandatory requirements for gasoline fuel systems in 33 CFR , Subpart J, Sections 183.501 - 183.590. Refer to the CFR for complete, current federal requirements.


Is that required of manufacturers or all vessels on the water?

[rbgarr]

The issue is less with any CG fine than it is with safety, the CFR and insurance should their be an explosion, etc. and making a claim.

[ssor]

In the early days of aviation all of the fluid lines were copper and periodic maintenance required the removal of the lines for annealing at specified intervals to prevent cracking as a result of work hardening due to vibration. When aluminum tubing became available they chose alloys that didn't work harden.