Fuel line

[Bob S]

I was going to replace some of the fuel line on my boat. The piece going from the pump has been rubbing against the throttle cable and has worn a groove into it. What is the difference between marine grade verses automotive fuel line besides the price?

 

[Stu Jackson]

Safety.

Material inside (gas vs. diesel).

 

[tommays]

At least on Gas its rated A1 for fuel line and A2 for tank fills and vents

It has passed a burn test to allow time to keep a small fire small

 

[Tim R.]

Make sure you use the USCG approved hose and cover it with some cheap nylon tubing where that grove occurred to prevent chafe in the future.

 

[Bob S]

I have 20’ of this line. I purchased it through McMaster Carr. The SAE-30R7-KX. I was going to use it to replace where ever it will fit. I googled the SAE# and found this:


For conveying fuel in automobiles, trucks, buses, etc.. SAE 30R7 type B USCG approved fuel line hose. Not designed for marine use with alcohol blended fuels.
Application:
Tube - Black Nitrile
Reinforcement - Spiral synthetic cord.
Cover - Black synthetic, Nitrile / PVC blend restistant to oil, grease and ozone.
Branding - Size SAE 30R7-KX date, Made in U.S.A.


Low-Pressure SAE Fuel Hose

• Use with diesel fuel and gasoline with up to 15% ethanol
• Temperature Range: -29° to +257° F
• Color: Black
• Hose: Buna-N (nitrile) rubber
• Cover: Blended Buna-N rubber/PVC
• Reinforcement: Polyester yarn spiral

Designed for inline connecting of fuel lines, this hose meets SAE 30R7 standards. Hose interior is smooth for unrestricted flow. Can be used indoors and out. Vacuum rating is 24” Hg @ 72° F.
To Order: Please order in 5-ft. increments up to the full coil length of 100 feet.
Click here for information about chemical compatibility.

 

[thinwater]

A major difference is the consequence of fire

In a car, you step away.

2 summers ago we had a fan start smoking (Hella Turbo--3 of them burned up within 7 days--no common thread, just their time) while we were well off shore and many hours from any sort of help. It was morning and most were asleep, but my announcement of "I smell smoke" got them up and running as though they had been electrocuted. We found the source very quickly.

With a fire on a boat there is nowhere to go.

 

[jimmcgee]

Bob,
From what you posted it looks like the hose is Coast Guard approved and it's rated for diesel. As long as your MK III still has a diesel you should be OK.

I wouldn't use it for the fuel supply on your dinghy outboard though as it's only rated for E15 gas, and higher ethanol blends are supposed to be on the horizon.

Jim

 

[Maine Sail]

I was going to replace some of the fuel line on my boat. The piece going from the pump has been rubbing against the throttle cable and has worn a groove into it. What is the difference between marine grade verses automotive fuel line besides the price?

I would NOT advise using automotive grade as your insurance company would not like it much if you lost your boat in a fire and the USCG and EPA would not like it much if your bilge pump dumped fuel overboard due to a hose failure.. You want a USCG hose rated A-1, A1-15 or A-2

(Some "A" rated fuel hose is not meant to be used with hose clamps and is instead intended for swaging machines and specific barbed fittings.)


From ABYC H-33:


33.6 FLEXIBLE FUEL HOSE
33.6.1 Hose shall comply with the requirements of SAE J1527, Marine Fuel Hoses.

33.6.1.1 Flexible hose shall be marked on the outermost cover with the manufacturer's name or trademark, year of manufacture, the applicable hose marking in H-33 Table I, and

33.6.1.1.2 All required markings must be legible and permanent on the hose itself, in block capital letters at least every 12 inches (304.8mm), and numerals at least 1/8 inch (3.16mm) high.

NOTE: Hoses less than 12 inches (305mm) in length may be tagged with the required marking.

33.14.5 Flexible hose shall be USCG Type A-1, A-2 or A1-15 (see H-33 TABLE I) if the line is within an engine compartment.

33.14.5.1 All fuel distribution and return lines located outside the engine compartment shall be of the type specified in H-33.14.6, or

33.14.5.2 shall be USCG Type A-1, A-2 or A1-15 or

33.14.5.3 USCG Type B-1, B-2 or B1-15 if a break at any point in this system will result in the discharge of no more than five ounces (147 cc) of fuel in 2-1/2 minutes when the hose is severed at the point where maximum drainage of fuel would occur, with the boat in its static floating position and fuel system is filled to capacity.

 

[Bob S]

Stu,

I'm hoping you might know the hose size between the fuel pump and the secondary filter. I want to buy a marine grade line before going to the boat. It's an hour trip each way.

I'm curious if it really matters on our M25XP's. 1/4" ID should be able to supply as much fuel as the engine can drink don't you think? Is there any advantage to a larger ID?

 

[Stu Jackson]

Bob, no, but you might want to take into consideration the size of the existing hoses and their barbs to the Racor. The fuel supply line is 3/8" supply, 5/16" return and a few very small lines between the injectors (1/4"?).

Why have to change the barbs? Match the new hose to the old hoses.

And remember: tank, Racor, fuel pump, engine, if you haven't already corrected that.

 

[Bob S]

And remember: tank, Racor, fuel pump, engine, if you haven't already corrected that.

My boat was set up that way (tank, Racor, fuel pump, secondary filter, engine).

SBO has pretty good pricing on Trident Marine Hose: Barrier A1 Marine Fuel Hose in 50' spools. I was thinking of buying a spool which would be more than enough to replace all my fuel line but it would all be the same size. Any opinions?

 

[Stu Jackson]

Bob, no reason to not use all the same size, but, like I said before, the barb connections will be different, so you'll have work to do there at the engine and the tank on the return side.

 

[Bob S]

Thanks Stu,

SBO is out of stock on the 3/8 ID. They are going to check availability for me. They do have 5/16 in stock.
I wonder why Catalina used different sizes. It would have been a lot easier if it was all the same. Guess that is a way to save money.

 

[Stu Jackson]

No, no, no --- Catalina didn't do it. It came that way from Universal/Westerbeke/Kubota. It's a tractor engine, remember.

We all need to remember that boat builders build a hull around parts by others...