Fuel Line Fabrication

[hanschristian38]

I have a project ahead which will require redoing most of the fuel lines on the boat. Does anyone know of a good source for information on products to use?

Copper tubing with compression or flared fittings?
Fuel manifolds?
Valves including diversion valves?

Is it better to use flexible hose?

[delmarrey]

IMHO flexible fuel line is better. Will not corrode, crack and less likely to leak at the fittings after vibration.
There is a specified USCG approved fuel line that is "fire resistant" that you should use.



Fisheries Supply

Originally Posted by ABYC

Fuel Hose: When fuel hose is used it must be either USCG Type A1, USCG Type A2, USCG Type B1 or USCG type B2. Where you use it determines what type you use.

From the fuel inlet on the engine (usually the fuel pump) to the carburetor you must use Type A1 or A2.

Each fuel vent line or fill line must be USCG Type A1 or A2 and the line from the fuel tank to the engine inlet must be type A1 or A2;.............................and so on....

New Boatbuilders Home Page - Fuel Systems

[Mark Zarley]

Fuel valves should be ball valves with a SS ball. My original fuel manifold was copper and all seams and fittings were soldered in. I replaced with a solid block of Aluminum and drilled it out for the passages and used a pipe tap for the ball valves. All joints were mechical ,note that alum and the brass from the valve should not touch so used a SS reducer between them. Had to do the same thing when I replaced my black iron tanks with alum. My fuel is diesel and that said I have 31 yr old copper tubing with flare fittings. Secret is no movement (vibration) allowed in the copper lines. Compression fittings would be easier (less operator error in the make up) and sometimes the flare will develop a small crack when removed and reinstalled - seepage or harder to find an air leak results. If using hose would go with wrench tightened fittings (think hydraulic hose type fittings). If you go with copper you will still need hose from the fuel pump to stringer or wherever copper supply line is securely fastened. Also for the fuel return. If the copper is taken directly to the eng harmonic vibration will soon ruin them. Good luck on your project

[Blue Stocking]

[. Compression fittings would be easier ]

Are these allowed in fuel systems ?

[barnakiel]

In my boat the engine ends and short pieces (from secondary on, are still original hard tubing, no leaks nor other issues. Also the tank fittings are on hard tubing. But anything low press and between the tank and the engine is rubber. Works OK.

The original soft tubing had press-on fittings, very neat and service free. But in NZ the mechanic could not fabricate them and now part is fitted with hose clamps. He fitted (???) and I had to replace all of them two months later. So I thing with rubber hose the original solution is better.

b.