Fuel / Carburetion System | Mercury Outboard

Fuel Pump Kit 115

The Fuel Pump Kit 115 is a Pro Marine rebuild kit designed for Mercury and Mariner inline 6-cylinder 2-stroke outboards. This kit restores proper fuel delivery by replacing worn internal components in diaphragm-style mechanical fuel pumps.

Fitment Overview

This kit replaces Mercury OEM part numbers 66599A3 and 89031A3, along with Sierra 18-7813, GLM 40370, and Mallory 9-37752. These cross reference numbers identify the Mercury inline-6 fuel pump family used on 90HP, 115HP, and 140HP engines.

Compatibility

Brand	Horsepower	Engine Type
Mercury	90 HP	Inline 6-Cylinder 2-Stroke
Mercury	115 HP	Inline 6-Cylinder 2-Stroke
Mercury	140 HP	Inline 6-Cylinder 2-Stroke
Mariner	90 HP	Inline 6-Cylinder 2-Stroke
Mariner	115 HP	Inline 6-Cylinder 2-Stroke
Mariner	140 HP	Inline 6-Cylinder 2-Stroke

These engines share a common diaphragm-style fuel pump design tied to the 66599A3 / 89031A3 fuel pump assembly.

Example Model Applications

• Mercury 90HP inline-6 2-stroke models (late 1970s–1980s)
• Mercury 115HP inline-6 2-stroke models
• Mercury 140HP inline-6 2-stroke models
• Mariner equivalents using the same fuel pump assembly

These are typical applications for this fuel pump kit. Always verify by matching your OEM part number or fuel pump assembly before ordering.

Fits These Serial Ranges

This fuel pump kit is used across multiple Mercury inline-6 engine generations and does not follow a single serial-number break.

Important: Confirm compatibility by matching your existing fuel pump or OEM number to 66599A3, 89031A3, 18-7813, 40370, or 9-37752.

Using a different pump style? This engine family may also use an alternate A1-style kit.
View Sierra 18-7811 Fuel Pump Kit (A1 Style)

Part Numbers and Cross References

Type	Part Number
Pro Marine	115
Mercury OEM	66599A3
Mercury OEM	89031A3
Sierra	18-7813
GLM	40370
Mallory	9-37752

What This Part Is Used For

This kit rebuilds mechanical diaphragm fuel pumps by replacing worn internal components such as diaphragms, gaskets, and valves. Proper fuel pump operation is essential for maintaining consistent fuel delivery to the engine.

• Restores proper fuel pressure and flow
• Replaces worn diaphragms and seals
• Helps eliminate fuel starvation issues
• Supports smooth engine performance

A failing fuel pump can cause hard starting, hesitation, loss of power, or engine stalling.

System Function and Connections

• System Type: Mechanical fuel delivery system
• Pump Type: Diaphragm fuel pump
• Location: Engine-mounted fuel pump assembly

FAQ

What engines does this kit fit?
It fits Mercury and Mariner inline 6-cylinder 2-stroke outboards in the 90HP, 115HP, and 140HP range using this fuel pump style.

What is the difference between this and the A1 kit?
This kit fits the A3-style fuel pump (66599A3 / 89031A3). Some engines use a different pump design that requires the A1-style kit.

How do I confirm fitment?
Match your fuel pump number or OEM part number to the cross references listed above.

What are signs of a bad fuel pump?
Hard starting, poor acceleration, fuel starvation, or engine stalling.

Dealer Discounts & Store Policies

Dealer / Marine Industry Discounts

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Shipping Policy

• Free shipping on orders over $100 (continental U.S.).
• Orders ship via UPS, USPS, and FedEx.
• Orders received before 5:30 PM EST ship the same business day.
• Typical delivery time is 1–5 business days.

30-Day Return Policy

• Returns accepted within 30 days of delivery.
• Items must be new, unused, and in original packaging.
• Return authorization is required before sending items back.

Need help with a return or order question?
Contact Us
Phone: 941-721-3000

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Searchable Part Numbers

115 fuel pump kit, 66599A3, 89031A3, 18-7813, 40370, 9-37752, Mercury inline 6 fuel pump rebuild kit

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