Primer Bulb

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.

Searchable Part Numbers & Terms

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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 assembly
• Refilling the line after fuel-system service
• Purging air from the fuel hose
• Replacing an old, hardened or damaged primer bulb

Compatible 3/8" Fuel Hose Options

Pro Marine stocks both Type A and Type B 3/8" marine fuel hose for use with the 8005 primer bulb.

3/8" Type B Marine Fuel Hose - 375

Bulk 3/8" Type B marine fuel hose for exposed and above-deck applications where Type B hose is appropriate.

Inside Diameter: 3/8"
Sold: By the Foot
Matching Clamp: Oetiker 4-185

View 3/8" Type B Fuel Hose

3/8" Type A Marine Fuel Hose - 375-1

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

Inside Diameter: 3/8"
Sold: By the Foot
Matching Clamp: Oetiker 4-185

View 3/8" Type A Fuel Hose

Correct Clamp for 3/8" Fuel Hose

Both the Type A and Type B 3/8" fuel hoses listed here use the same Oetiker 4-185 ear clamp.

Fuel Line Clamp and Installation Tools

Oetiker 4-185 Ear Clamp - 10 Pack

Matching clamp for both the 375 Type B and 375-1 Type A 3/8" marine fuel hoses.

View Oetiker 4-185 Clamp

Oetiker Standard Jaw Pincer Tool

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

View Oetiker Pincer Tool

Oetiker Clamp Pack with Tool

Complete assortment of commonly used Oetiker clamp sizes with the installation tool included.

A convenient option for marine shops, technicians and customers servicing multiple fuel-line sizes.

View Oetiker Clamp Pack

How a Primer Bulb Works

The primer bulb contains internal one-way check valves that control the direction of fuel flow.

As the bulb is squeezed and released, it draws fuel from the tank and moves it toward the engine. Repeated squeezes fill the hose and help purge air from the fuel line.

Primer Bulb Installation

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

Secure the hose at the primer bulb and other barbed fittings using the correct Oetiker clamps.

When Should a Primer Bulb Be Replaced?

Fuel, heat, UV exposure and normal use can cause primer bulbs to 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 after squeezing
• A bulb that will not become firm while priming
• Fuel leakage around the bulb or fittings
• Air entering the fuel system
• Internal check-valve failure

Building a Complete 3/8" Outboard Fuel Line

Depending on the application, a complete 3/8" fuel-line setup may require:

• Pro Marine 8005 3/8" primer bulb
• 375 Type B or 375-1 Type A 3/8" fuel hose
• Correct tank-side fitting or connector
• Correct engine-side fitting or connector
• Oetiker 4-185 ear clamps
• Oetiker pincer installation tool

Type A or Type B Fuel Hose?

The Pro Marine 8005 primer bulb can be used with either listed hose because both use a 3/8" inside diameter.

Type B 375 is commonly used in exposed and above-deck applications where Type B hose is appropriate.

Type A 375-1 is used when the installation requires the additional Type A fire-resistant classification, including many enclosed and below-deck fuel-system applications.

Key Features

• Pro Marine 8005 marine primer bulb
• Designed for 3/8" ID marine fuel hose
• Compatible with 375 Type B fuel hose
• Compatible with 375-1 Type A fuel hose
• Used to manually prime outboard fuel systems
• Helps draw fuel from the tank toward the engine
• Both compatible hoses use Oetiker 4-185 clamps
• Oetiker pincer installation tool available
• Complete Oetiker clamp assortment with tool available

Need Help Building Your Marine Fuel Line?

Choosing the right marine fuel-line setup involves matching hose diameter, Type A or Type B classification, primer bulb size, fittings and the correct clamp.

Visit the Pro Marine Fuel Line Technical Center

FAQ

What size hose does the Pro Marine 8005 primer bulb fit?
The 8005 is designed for 3/8" ID fuel hose.

Can I use this primer bulb with Type B fuel hose?
Yes. It fits the 375 3/8" Type B fuel hose .

Can I use this primer bulb with Type A fuel hose?
Yes. It also fits the 375-1 3/8" Type A fuel hose .

Which clamp fits the 3/8" Type B hose?
Use the Oetiker 4-185 ear clamp .

Which clamp fits the 3/8" Type A hose?
The Type A hose also uses the Oetiker 4-185 ear clamp .

Do Type A and Type B 3/8" hose use the same clamp?
Yes. Both 3/8" hose options listed here use the Oetiker 4-185 clamp.

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

What tool installs the Oetiker clamp?
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.

Searchable Part Numbers & Terms

8005, Pro Marine 8005, 3/8 primer bulb, 3/8 marine primer bulb, outboard primer bulb, boat fuel primer bulb, marine fuel bulb, outboard fuel bulb, 3/8 fuel line, 3/8 outboard fuel hose, 375, 3/8 Type B fuel hose, 375-1, 3/8 Type A fuel hose, Oetiker 4-185, 4-185 fuel hose clamp, marine fuel line clamp, Oetiker fuel line clamp, primer bulb fuel line, marine fuel system, outboard fuel line, boat fuel line

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 the bulb draws fuel from the fuel tank and pushes it toward the engine. Internal check valves help direct fuel flow in the correct direction.

Primer bulbs are commonly used when:

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

Compatible Fuel Hose

Pro Marine stocks both Type A and Type B 1/4" marine fuel hose for use with this primer bulb.

MPI 1/4" Type B Marine Fuel Hose - 315-014

Bulk 1/4" marine fuel hose for exposed and above-deck applications where Type B hose is appropriate.

Inside Diameter: 1/4"
Sold: By the Foot
Matching Clamp: Oetiker 4-133

View 1/4" Type B Fuel Hose

MPI 1/4" Type A Marine Fuel Hose - 314-1

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

Inside Diameter: 1/4"
Sold: By the Foot
Matching Clamp: Oetiker 4-170

View 1/4" Type A Fuel Hose

Correct Clamp for Each 1/4" Fuel Hose

Both hoses use a 1/4" inside diameter, but their outside diameters are different because of their construction and wall thickness. This means they require different Oetiker clamps.

Fuel Line Clamps and Installation Tools

Oetiker 4-133 Ear Clamp - 10 Pack

Correct clamp for the MPI 315-014 1/4" Type B fuel hose.

View Oetiker 4-133 Clamp

Oetiker 4-170 Ear Clamp - 10 Pack

Correct clamp for the MPI 314-1 1/4" Type A fuel hose.

View Oetiker 4-170 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

A complete assortment of commonly used Oetiker clamp sizes with the installation tool included.

A convenient option for marine shops, technicians or anyone servicing multiple fuel-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, these valves allow fuel to move in one direction through the fuel line.

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

Primer Bulb Installation

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

A typical fuel path is:

Secure each hose connection using the clamp matched to the specific fuel hose being installed.

When Should a Primer Bulb Be Replaced?

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

Inspect or replace the primer bulb if you notice:

• Cracking or surface deterioration
• A bulb that has become excessively hard
• A bulb that stays collapsed
• A bulb that will not become firm when priming
• Fuel leakage around the bulb or fittings
• Air entering the fuel line
• Internal check-valve problems

Building a Complete 1/4" Outboard Fuel Line

Depending on your installation, a complete 1/4" fuel-line assembly may require:

• Pro Marine 8002 1/4" primer bulb
• 1/4" Type A or Type B marine fuel hose
• Correct engine-side connector or fitting
• Correct tank-side connector or fitting
• Correct Oetiker clamps for the selected hose
• Oetiker pincer tool

Type A or Type B Fuel Hose?

The primer bulb works with either of the 1/4" hose options because both have the same 1/4" inside diameter.

The correct hose classification depends on the fuel-system installation.

Type B is commonly used in exposed and above-deck installations where Type B hose is permitted.

Type A is used where the installation requires the additional Type A fire-resistant classification, including many enclosed and below-deck fuel-system applications.

Key Features

• Pro Marine 8002 marine primer bulb
• Designed for 1/4" ID marine fuel hose
• Compatible with MPI 315-014 Type B fuel hose
• Compatible with MPI 314-1 Type A fuel hose
• Used to manually prime outboard fuel systems
• Helps draw fuel from the tank toward the engine
• Type B Oetiker 4-133 clamps available
• Type A Oetiker 4-170 clamps available
• Oetiker installation pincer available
• Complete Oetiker clamp assortment with tool available

Need Help Building Your Marine Fuel Line?

Hose size, Type A or Type B 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 8002 primer bulb fit?
The 8002 is designed for 1/4" ID fuel hose.

Can I use this primer bulb with Type A fuel hose?
Yes. It can be used with the MPI 314-1 1/4" Type A hose .

Can I use it with Type B fuel hose?
Yes. It also fits the MPI 315-014 1/4" Type B hose .

Which clamp fits the 1/4" Type B hose?
Use the Oetiker 4-133 ear clamp .

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

Why do the Type A and Type B hoses use different clamps?
Both hoses have a 1/4" inside diameter, but their outside diameters differ because of their construction and wall thickness. Clamp size must match the outside diameter of the specific hose.

Which direction should the primer bulb be installed?
Install the primer bulb 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 an installation tool.

Searchable Part Numbers & Terms

8002, Pro Marine 8002, 1/4 primer bulb, 1/4 marine primer bulb, outboard primer bulb, boat fuel primer bulb, marine fuel bulb, outboard fuel bulb, 1/4 fuel line, 1/4 outboard fuel hose, 315-014, MPI 315-014, 1/4 Type B fuel hose, 314-1, MPI 314-1, 1/4 Type A fuel hose, Oetiker 4-133, Oetiker 4-170, marine fuel line clamp, Oetiker fuel line clamp, primer bulb fuel line, marine fuel system, outboard fuel line