Attwood Marine Fuel Primer Bulb, Low Permeation, EPA/CARB Certified

Overview

This Attwood Marine primer bulb is a low-permeation hand primer for outboard fuel lines, available for 1/4", 5/16", and 3/8" inner diameter hose setups. It is used in the fuel line between a portable tank or onboard fuel supply and the engine, helping pull fuel through the line before starting.

The bulb uses a three-layer construction that resists collapse under vacuum and helps prevent ballooning or bursting under pressure. Its low-permeation material reduces fuel evaporation, while high-efficiency check valves support faster priming with low fuel restriction, including less than 1 kPa restriction at 50 liters per hour.

This is a practical replacement or rigging part for small outboards, tenders, fishing boats, and other gasoline-powered marine setups where the fuel line size needs to match the engine and tank connections. The bulb is compatible with ethanol-blended fuels and is EPA and CARB certified.

Key features

• Low-permeation bulb helps reduce fuel evaporation in portable and outboard fuel systems.
• Three-layer construction resists vacuum collapse and pressure-related ballooning.
• High-efficiency check valves help the line prime quickly with fewer hand pumps.
• Low fuel restriction, rated at less than 1 kPa at 50 liters per hour.
• Works with ethanol-blended fuels used in many marine gasoline systems.
• Operating temperature range of 18°F to 122°F supports typical seasonal boating conditions.
• EPA and CARB certified for compliant fuel-system service.
• Available in 1/4", 5/16", and 3/8" hose inner diameter versions for common outboard fuel line sizes.

Variants

This primer bulb range is offered in multiple hose inner diameter configurations so the fuel line connection can match the existing hose on the boat or engine rig.

The hose size is the key difference between the variants. The priming construction, low-permeation purpose, ethanol compatibility, and EPA and CARB certification are consistent across the listed versions.

• 93014LP7: 1/4" inner diameter hose. This size fits fuel line systems that use 1/4" ID hose, often found on smaller outboard and portable fuel setups.
• 93038LP7: 3/8" inner diameter hose. This version is for fuel systems using 3/8" ID hose where a larger fuel line is already part of the rigging.
• 93516LP7: 5/16" inner diameter hose. This size suits installations built around 5/16" ID fuel hose, a common middle size for many outboard applications.

Installation and fit

Match the variant to the inner diameter of the existing marine fuel hose, not the outside diameter. A primer bulb that does not match the hose size can be hard to seal and may create fuel delivery problems, especially when the line is under suction from the engine fuel pump.

Install the bulb in the correct fuel-flow direction, with the arrow or flow marking pointing toward the engine. It should be placed where it can be reached by hand, away from sharp bends, engine heat, and areas where gear or feet can press against the fuel line.

Use on board

This primer bulb is a good match for boaters replacing an old, stiff, or slow-priming bulb in an outboard fuel line. It is also useful when rigging a new portable fuel tank hose assembly for a dinghy, skiff, jon boat, center console, or fishing boat.

For best results, inspect the full fuel line at the same time, including hose condition, clamps, connectors, and tank fittings. A fresh primer bulb can only work properly when the rest of the fuel path is clean, sealed, and sized correctly.