Pro Marine 5/16" Primer Bulb - 8004

What This Primer Bulb is Used For

A primer bulb is installed inline in an outboard fuel hose and acts as a manual fuel pump.

Squeezing and releasing the bulb draws fuel from the tank and pushes it toward the engine. Internal one-way check valves help keep fuel moving in the proper direction.

Primer bulbs are commonly used when:

• Starting an outboard after the fuel line has drained
• Priming a newly installed fuel line
• Refilling the line after fuel-system service
• Purging air from the fuel hose
• Replacing an old, hardened or damaged primer bulb

Compatible 5/16" Fuel Hose Options

Pro Marine stocks three common 5/16" fuel-hose options that can be used with this primer bulb. The correct hose depends on the installation and required fuel-hose classification.

MPI 5/16" Type B Fuel Hose - 315-056

5/16" Type B marine fuel hose commonly used in exposed and above-deck applications where Type B hose is appropriate.

Inside Diameter: 5/16"
Sold: By the Foot
Matching Clamp: Oetiker 4-153

View 5/16" Type B Fuel Hose

MPI 5/16" Type A Fuel Hose - 313-1

Type A marine fuel hose for installations requiring the additional Type A fire-resistant classification.

Inside Diameter: 5/16"
Sold: By the Foot
Matching Clamp: Oetiker 4-170

View 5/16" Type A Fuel Hose

Mercury OEM 5/16" Silver Fuel Hose

Genuine Mercury Marine bulk 5/16" fuel hose for compatible Mercury outboard fuel-line applications.

Inside Diameter: 5/16"
Sold: By the Foot
Matching Clamp: Oetiker 4-145

View Mercury OEM Fuel Hose

Correct Clamp for Each 5/16" Fuel Hose

All three hoses have a 5/16" inside diameter, but they do not have the same outside diameter. Different constructions and wall thicknesses require different Oetiker clamp sizes.

Fuel Line Clamps and Installation Tools

Oetiker 4-153 Ear Clamp - 10 Pack

Correct clamp for the MPI 315-056 5/16" Type B fuel hose.

View Oetiker 4-153 Clamp

Oetiker 4-170 Ear Clamp - 10 Pack

Correct clamp for the MPI 313-1 5/16" Type A fuel hose.

View Oetiker 4-170 Clamp

Oetiker 4-145 Ear Clamp - 10 Pack

Correct clamp for the Mercury OEM 5/16" silver fuel hose.

View Oetiker 4-145 Clamp

Oetiker Standard Jaw Pincer Tool

Installation tool for properly closing Oetiker ear clamps when assembling marine fuel-line connections.

View Oetiker Pincer Tool

Oetiker Clamp Pack with Tool

Assortment of common Oetiker clamp sizes with the installation tool included. A convenient option for marine shops and technicians working with multiple hose sizes.

View Oetiker Clamp Pack

How a Primer Bulb Works

The primer bulb contains internal one-way check valves. When the bulb is squeezed and released, the valves allow fuel to move in one direction through the hose.

Repeatedly squeezing the bulb draws fuel from the fuel tank, fills the fuel line and supplies fuel toward the engine.

Primer Bulb Installation

Install the primer bulb with the fuel-flow arrow pointing toward the engine.

Secure each hose connection using the correct clamp for the specific fuel hose being installed.

When Should a Primer Bulb Be Replaced?

Primer bulbs are continually exposed to fuel, heat and the marine environment and can deteriorate over time.

Inspect or replace the primer bulb if you notice:

• Cracking or visible deterioration
• A bulb that has become excessively hard
• A bulb that stays collapsed
• A bulb that will not become firm when priming
• Fuel leaking around the bulb or hose connections
• Air entering the fuel system
• Internal check-valve problems

Building a Complete 5/16" Outboard Fuel Line

Depending on the installation, a complete 5/16" fuel-line assembly may require:

• Pro Marine 8004 5/16" primer bulb
• 5/16" Type A, Type B or Mercury OEM fuel hose
• Correct tank-side connector or fitting
• Correct engine-side connector or fitting
• Correct Oetiker clamps for the selected hose
• Oetiker pincer installation tool

Type A, Type B or Mercury OEM Fuel Hose?

The Pro Marine 8004 primer bulb fits all three listed hose options because each hose has a 5/16" inside diameter.

The difference is in the hose construction and intended installation.

MPI Type B 315-056 is commonly used in exposed and above-deck applications where Type B hose is permitted.

MPI Type A 313-1 is used where the installation requires the additional Type A fire-resistant classification.

Mercury OEM #100 is the genuine Mercury 5/16" silver fuel-hose option for compatible Mercury fuel-line applications.

Key Features

• Pro Marine 8004 marine fuel primer bulb
• Designed for 5/16" ID fuel hose
• Compatible with MPI 315-056 Type B hose
• Compatible with MPI 313-1 Type A hose
• Compatible with Mercury OEM #100 5/16" silver hose
• Used to manually prime outboard fuel systems
• Helps draw fuel from the tank toward the engine
• Matching Oetiker clamps available for each hose
• Oetiker pincer installation tool available
• Complete Oetiker clamp assortment with tool available

Need Help Building Your Marine Fuel Line?

Hose size, fuel-hose classification, primer bulb size and clamp selection all need to match the fuel-system installation.

Visit the Pro Marine Fuel Line Technical Center

FAQ

What size hose does the Pro Marine 8004 primer bulb fit?
The 8004 is designed for 5/16" ID fuel hose.

Can I use this primer bulb with MPI Type B hose?
Yes. It fits the MPI 315-056 5/16" Type B fuel hose .

Can I use it with Type A hose?
Yes. It also fits the MPI 313-1 5/16" Type A fuel hose .

Can I use it with Mercury OEM 5/16" silver fuel hose?
Yes. The Mercury OEM #100 5/16" silver hose also has a 5/16" inside diameter.

Which clamp fits MPI 315-056 Type B hose?
Use the Oetiker 4-153 ear clamp .

Which clamp fits MPI 313-1 Type A hose?
Use the Oetiker 4-170 ear clamp .

Which clamp fits the Mercury OEM 5/16" hose?
Use the Oetiker 4-145 ear clamp .

Why do all three 5/16" hoses use different clamps?
The 5/16" measurement refers to the inside diameter. Each hose has a different construction and outside diameter, so each requires the correct clamp matched to that hose.

Which direction should the primer bulb be installed?
Install it with the fuel-flow arrow pointing toward the engine.

What tool is used to install Oetiker clamps?
Use the Oetiker Standard Jaw Pincer Tool .

Do you sell a clamp assortment?
Yes. The Oetiker Clamp Pack with Tool includes common clamp sizes and the installation tool.

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