Sierra 368 Marine Fuel Feed Hose 3/8 in x 50 ft Low Permeation

If you're re-plumbing a fuel system or just chasing down a soft, weeping old line, the Sierra Series 368 is the hose you want feeding your engine. It's a 3/8 inch inside diameter marine fuel feed hose in a 50 foot coil, built for the stuff that actually runs through boat fuel systems today. Gasoline up to 85 percent ethanol. Diesel. Biodiesel in every blend. The lining is made to live with modern fuel without going soft or gummy on you.

The number that matters most here is low permeation. Older rubber fuel line lets fuel vapor seep right through the wall, which is bad for your nose, bad for the bilge, and these days it's against the rules. This hose is A1-15 certified, the low-permeation standard that meets EPA evaporative-emission requirements for marine fuel lines. So it keeps the fuel where it belongs and keeps you legal. The A1 part of that rating also means it's a fire-resistant construction, which is why it's approved for below-deck fuel lines where a plain hose isn't. The cover is black reinforced polyester, and it shrugs off fuel, oil, and the salt-and-heat abuse of a working engine bay.

Let's talk pressure, because this is where people get tripped up. The 368 is rated to 100 PSI maximum. That's plenty for fuel feed and return lines running off a low-pressure lift pump or a primer bulb. It is not a high-pressure injection hose. If you're plumbing the high side of a modern EFI or common-rail diesel, you need dedicated high-pressure line, not this. Use the 368 where it belongs, on the supply and return side, and it'll outlast the boat.

Sizing is straightforward. The 3/8 inch ID is the fuel path, and it slips over a standard 3/8 inch barb. The 11/16 inch OD is the outside of the hose, which is what you measure for clamp sizing and for figuring clearance through a tight bulkhead. One thing we've run into: some OEM tank nipples are sized a hair different, so dry-fit before you commit and grab the right barb adapter if you need one. Better to sort that at the bench than hanging upside down in a lazarette.

A few install tips from doing this a bunch. Fifty feet of hose ships as a coil, and a cold coil can fight you on tight bilge runs. Warm it up first. A little time in the sun or a soak in warm water makes it far more willing to bend. Avoid sharp kinks, support long runs with cushioned clamps every foot or so, and double-clamp both ends on outboards and anywhere there's real vibration. That's cheap insurance against a fuel leak. And route the hose out of constant direct sunlight where you can, or sleeve it in split conduit. UV is the enemy of any hose cover over the long haul.

Fifty feet is generous. On a small runabout you'll have plenty left over, so cut what you need and store the remainder coiled flat so it doesn't take a permanent set. On a bigger inboard or a twin-engine rig, that length lets you do the whole fuel system in one shot with matching hose end to end. Pair it with a good 10-micron fuel-water separator and a primer bulb and you've got a clean, reliable feed that handles ethanol gas even when the engine compartment gets hot.

Who's this for? Outboard owners replacing brittle old primer-bulb hose, inboard owners doing a proper fuel-system refresh, sailboat auxiliary diesels, and anyone who wants one hose that covers both the gas and diesel boats in the fleet. If you run ethanol pump gas, this is the line that stops the slow degradation you get from cheap hose. And if you keep a diesel, the same coil handles biodiesel blends without a second thought.

Sierra builds parts to meet or beat the original equipment they replace, and this hose is no exception. It's the kind of unglamorous gear you install once and forget about, which is exactly what you want from a fuel line. Backed by Sierra's limited two-year warranty and our authorized-dealer support if you ever need it.