Sierra 18-7809 Fuel Pump Kit for Mercury Outboard, Replaces 55278A4

The Sierra 18-7809 Fuel Pump Kit is a replacement fuel pump built for Mercury Outboard engines, engineered to meet or exceed the specifications of the original equipment part it replaces. It functions as a direct equivalent to Mercury Marine OEM fuel pump 55278A4, giving boat owners a reliable way to restore correct fuel delivery without sourcing a factory-only part. The kit is constructed from aluminum and stainless steel for resistance to corrosion in the harsh marine environment, and it uses a bolted inlet connection paired with an FNPT outlet connection for a secure, leak-resistant fit. Operation is automatic and the pump is designed for tank-mount installation, matching the layout of the outboard fuel system it is intended to service.

This is a compact, precision-fit component at 0.39 x 0.39 x 0.39 inches and 0.02 pounds, so it installs into the existing fuel pump location without modification. Sierra manufactures this kit to the same standards it supplies to OEM engine builders and boat manufacturers, and the part is backed by Sierra's limited warranty.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-7809
• Product Category: Mercury Outboard Fuel Pump Kit
• Material: Aluminum, Stainless Steel
• Item Dimensions: 0.39 x 0.39 x 0.39 inches
• Weight: 0.02 pounds
• Inlet Connection Type: Bolted
• Inlet Connection Size: 0.5 inches
• Outlet Connection Type: FNPT
• Outlet Connection Size: 0.5 inches
• Mounting Type: Tank Mount
• Operation Mode: Automatic
• Fit Type: Universal Fit
• Gas Type: Gasoline
• Included Components: Fuel Pump Kit
• Warranty: Limited Warranty
• UPC: 808282259952

Fitment

• Mercury Outboard engines

Replaces (OEM)

• Mercury Marine 55278A4

Frequently Asked Questions

What does the Sierra 18-7809 fuel pump kit replace? The 18-7809 kit is a direct equivalent to Mercury Marine OEM fuel pump 55278A4, built to meet or exceed the original part's specifications.

What engines does the 18-7809 fuel pump kit fit? This fuel pump kit is designed for Mercury Outboard engines that originally used the Mercury Marine 55278A4 fuel pump.

What material is the Sierra 18-7809 made from? It is constructed from aluminum and stainless steel, chosen for corrosion resistance in marine use.

How is the 18-7809 fuel pump kit mounted? The pump uses a tank-mount design with a bolted inlet connection and an FNPT outlet connection.

Is the fuel pump operation manual or automatic? The Sierra 18-7809 fuel pump operates automatically once installed in the outboard's fuel system.

What are the dimensions of the 18-7809 fuel pump kit? It measures 0.39 x 0.39 x 0.39 inches, a compact size that fits the factory pump location without modification.

How much does the Sierra 18-7809 weigh? The kit weighs 0.02 pounds.

Is this fuel pump genuine OEM or aftermarket? The Sierra 18-7809 is an aftermarket replacement engineered to meet or exceed the specifications of the Mercury Marine OEM part 55278A4 it replaces.

What is included in the 18-7809 kit? The kit includes the fuel pump as a complete assembly, listed by Sierra as the Fuel Pump Kit component set.

What fuel type is the 18-7809 pump designed for? It is designed for gasoline fuel systems.

Does the Sierra 18-7809 come with a warranty? Yes, the fuel pump kit is backed by Sierra's limited warranty.

What size are the inlet and outlet connections on the 18-7809? Both the inlet and outlet connections on this fuel pump kit measure 0.5 inches, with a bolted inlet and an FNPT outlet.