Five Oceans 3/8" Fuel Line Primer Bulb — Large Universal Outboard Primer (EPA/CARB, Ethanol-Compatible)

Five Oceans 3/8-inch universal primer bulb (FO-4279) is a durable, EPA/CARB-approved fuel line bulb designed to reliably prime outboard motors and handle ethanol-blended fuels.

This large 3/8" inside-diameter primer bulb is built for marine use and comes with barb-end hose connectors and stainless-steel clamps for a secure installation. Constructed from multi-layer, low-permeation material, the bulb resists weather, UV degradation, and the corrosive effects of modern gasoline blends — including up to 85% ethanol gasoline, diesel, and biodiesel blends. The FO-4279 meets current Environmental Protection Agency and CARB regulations, making it a suitable upgrade or replacement for many recreational and commercial boats.

How does this primer bulb make starting an outboard easier?

The primer bulb creates positive fuel flow from the tank to the engine, removing air pockets and restoring pressure before ignition. Its large 3/8" bore delivers higher volume flow for quick, effective priming, especially after long idle periods or fuel system maintenance.

• 3/8" inside diameter for stronger suction and faster fuel delivery
• Barb-end connectors and clamps included for immediate installation
• Multi-layer construction reduces fuel vapor permeation that causes poor priming
• Compatible with gasoline, diesel, and ethanol/biodiesel blends to handle modern fuels

Will this primer bulb fit my fuel line and how easy is it to install?

FO-4279 is intended for fuel hoses with a 3/8" inside diameter and includes barb fittings sized for a snug fit. Installation is straightforward: cut the fuel line where needed, push the hose onto the barb, and tighten the supplied stainless-steel clamps for a leak-resistant connection.

• Designed for 3/8" ID fuel hose — common on many outboards and small craft
• Comes with barb connectors already attached to the bulb for convenience
• Stainless-steel hose clamps included to prevent leaks and corrosion
• Simple inline replacement with no special tools required beyond pliers and a screwdriver

Is this primer bulb safe for ethanol and environmentally compliant?

The bulb's low-permeation, multi-layer material is engineered to tolerate ethanol-blended fuels up to 85% and biodiesel formulations, helping reduce vapor loss and swelling that can degrade standard rubber. FO-4279 also meets EPA and CARB requirements, reflecting reduced emissions and regulatory compliance for vehicles and vessels operating in regulated areas.

• Compatible with gasoline up to 85% ethanol blends, diesel, and biodiesel
• Low-permeation layers minimize harmful vapor release
• EPA certified and CARB approved for compliant marine use
• Weather- and UV-resistant construction supports long service life

How long will this primer bulb last and what maintenance does it need?

Made from marine-grade materials, the FO-4279 is built to resist UV, weathering, and chemical attack from modern fuels, which extends useful life compared with standard single-layer bulbs. Periodic inspection for cracking, softening, or leaks is recommended; replacing the bulb at the first sign of deterioration prevents fuel delivery issues.

• Multi-layer construction for improved durability and reduced permeation
• UV- and weather-resistant for extended outdoor use
• Inspect clamps and hose connections annually or after heavy use
• Replace immediately if you notice loss of prime, cracks, or leaks

Who is this for: The Five Oceans FO-4279 primer bulb is ideal for boat owners, mechanics, and marine rental operators who need a reliable, regulation-compliant inline primer bulb for 3/8" fuel hose. It suits vessels using modern ethanol-blended gasoline, diesel, or biodiesel, and anyone seeking a durable replacement that installs quickly and resists weather and fuel-related degradation.