2PCS 5/8" Polypropylene Fuel Vent, Plastic Marine Thru Hull Exhaust Applicable to Connecting Φ 16Mm Hose Ventilation Device,Black

Pump fuel into a sealed tank and the air already in there has to go somewhere. If it cannot escape, the filler burps back at you. Later, as the engine draws fuel out, the tank pulls a vacuum against itself and the pickup starts to starve. A hull vent gives the tank a way to breathe in both directions.

Breathes out on the fill, back in on the run

Displaced air leaves through the fitting while you are filling, which is what lets the nozzle keep flowing instead of stalling every few seconds. Once the engine is running and the level drops, air is drawn back in to take the fuel's place. The grille face is shaped to resist splash coming the other way, so slop in a seaway is far less likely to find its way out through the vent.

Polypropylene where salt air gets at it

Plastic sidesteps the corrosion that eventually claims a metal fitting in a marine installation. The supplier describes the material as resistant to ageing, high temperature and splash. A screw rod pulls the flange down against the mounting face, so the seal comes from the clamped flange rather than relying on the hose joint alone.

Key features

• Two per pack: enough for a twin-tank installation or a spare.
• Screw-rod clamping: tightens the flange down evenly by hand.
• Splash-resistant grille: vents air while shedding fuel thrown at it from inside.
• Takes 16 mm hose: the supplier states it connects to Φ16 mm vent hose.

Specifications

• Quantity: 2
• Material: polypropylene
• Colour: black
• Size: 5/8 in (from the product title)
• Hose connection: Φ16 mm (from the supplier description)
• Hose clamps: required, not stated as included
• Stated application: yachts and boats

Before you cut the hole

• This is a through-hull fitting. If you are not confident cutting and sealing a hull or tank face, have a marine trade do it.
• A fuel tank vent must discharge to open air, never into a cabin, locker or engine space where vapour can collect low down.
• The supplier names no marine fuel system standard or approval for this part — confirm what your vessel and survey requirements call for.
• Use fuel-rated vent hose and clamp both ends; ordinary garden or air hose is not suitable.
• Work with the tank as empty as practical, keep the space ventilated and keep ignition sources away.

Two in a pack, ready to plumb into a tank that is not venting as it should.