SeaSierra 3/8" (10mm) Universal Rubber Primer Bulb for Outboards — Manual Fuel-Transfer, Above-Deck

The SeaSierra 3/8" (10mm) universal rubber primer bulb is a direct-replacement fuel-transfer pump that manually draws gasoline from a marine tank to your outboard engine for easier starting.

Designed to fit most small- to mid-sized outboard setups, this rubber primer bulb works with a wide range of brands including Yamaha, Mercury, Mariner, Johnson, Evinrude, OMC, Tohatsu and Honda. Built for simple installation and routine maintenance, it restores proper fuel flow when the existing bulb becomes cracked, stiff, or ineffective. The SeaSierra primer bulb is sized for a 3/8" (10mm) inner-diameter fuel line and is intended for above-deck mounting away from constant sunlight and extreme heat to prolong life.

How will this primer bulb improve outboard starting?

If your boat hesitates or requires repeated pulls to start, an aged or leaking primer bulb can be the cause. Replacing it re-establishes a reliable hand-operated fuel transfer path so the engine gets the gasoline it needs for a quick, consistent start.

• Restores positive fuel draw from tank to carburetor or EFI unit
• Eliminates air leaks caused by hardened or cracked rubber
• Simple squeeze action provides immediate fuel transfer without tools

Will this SeaSierra bulb fit my fuel hose and outboard brand?

The SeaSierra primer bulb fits hoses with a 3/8" (10mm) inner diameter and is made to be compatible with most common outboard fittings. It’s a universal-style part, so in many cases it installs inline between the fuel tank and the engine without additional adapters.

• Inner diameter: 3/8" (10mm) — confirm your hose ID before purchase
• Compatible with many Yamaha, Mercury, Honda, Evinrude, Tohatsu, Johnson, Mariner and OMC systems
• Installed inline; clamps or booster clips recommended for secure connection

How do I install and care for this rubber primer bulb?

Installation is straightforward: cut the fuel line where needed, push each hose end onto the matching barb, and secure with stainless clamps. To prolong the rubber’s service life, avoid prolonged sun exposure and store spares in a cool, shaded place when not installed.

• Use hose clamps or crimp-style crimp clamps for leak-free seals
• Avoid direct UV and prolonged heat to prevent rubber deterioration
• Inspect periodically for cracks, stiffness, or fuel seepage and replace if found

What materials and limitations should I expect?

The primer bulb is molded from fuel-resistant rubber suitable for gasoline and typical marine fuel blends. It is designed for external, above-deck mounting; continuous exposure to sunlight, extreme heat, or harsh chemicals will shorten its useful life.

• Material: rubber formulated for fuel resistance
• Not intended for extended UV exposure — store and mount out of direct sun when possible
• Check compatibility with ethanol-blended fuels and local regulations if needed

Who is this for: The SeaSierra 3/8" (10mm) outboard primer bulb is ideal for boat owners, marinas, DIY mechanics, and watersports enthusiasts who need a reliable, economical replacement for a worn or failing fuel primer. If you operate small to mid-size outboard motors and your fuel line uses 3/8" inner-diameter hose, this universal rubber bulb gives an easy install and dependable manual fuel transfer to help your engine start and run smoothly.