Sierra 18-7788 Fuel Pump Kit, Replaces 6E5-24411-00-00, for Yamaha V-4 and V-6 Outboards

The Sierra 18-7788 Fuel Pump Kit is a mechanical fuel pump rebuild kit for Yamaha V-4 and V-6 outboard engines, engineered to restore the fuel pump diaphragm and gasket to factory sealing performance. Fuel pump diaphragms and gaskets harden and crack with age and exposure to modern fuels, leading to fuel leaks, rough idle, hesitation, or a pump that will not draw fuel at all. This kit replaces those wear items so the pump can rebuild pressure and deliver a steady fuel supply to the carburetors.

Kit 18-7788 contains two components: a rear gasket (18-7843) with an OEM equivalent number of 6E5-24411-00-00, and a top diaphragm (18-7842) with an OEM equivalent number of 6E5-24471-00-00. Both parts are sized and shaped to match the original Yamaha fuel pump assembly, so the pump housing seals correctly and pumps fuel without bypass leakage once reassembled. The kit uses a hose barb inlet and a barbed outlet connection sized for 0.5 inch fuel line, consistent with the tank-mounted, mechanically operated fuel pump design used on these outboards.

This kit is intended for technicians and boat owners rebuilding an existing Yamaha V-4 or V-6 outboard fuel pump rather than replacing the entire pump assembly, offering a lower-cost repair path when the pump body itself is still serviceable.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-7788
• Product Type: Fuel Pump Kit
• Engine Application: Yamaha V-4 and V-6 outboard engines
• Kit Contents: Gasket (Rear) 18-7843, Diaphragm (Top) 18-7842
• OEM Cross Reference: 6E5-24411-00-00
• Component OEM Numbers: Gasket (Rear) 6E5-24411-00-00; Diaphragm (Top) 6E5-24471-00-00
• Mounting Type: Tank Mount
• Operation Mode: Mechanical
• Inlet Connection: Hose Barb
• Outlet Connection: Barb, 0.5 inches
• Item Dimensions: 6.75 x 6 x 1 inches
• Weight: 0.02 pounds
• UPC: 808282105785

Fitment

• Yamaha V-4 and V-6 outboard engines

Replaces (OEM)

• 6E5-24411-00-00

Frequently Asked Questions

What does the Sierra 18-7788 Fuel Pump Kit fit? The 18-7788 kit fits Yamaha V-4 and V-6 outboard engines that use this fuel pump design.

What is included in kit 18-7788? The kit contains a rear gasket (part 18-7843) and a top diaphragm (part 18-7842) for the fuel pump.

What OEM number does the 18-7788 kit replace? It replaces OEM number 6E5-24411-00-00 on Yamaha V-4 and V-6 outboard fuel pumps.

Do the individual gasket and diaphragm have their own OEM numbers? Yes: the rear gasket 18-7843 corresponds to OEM 6E5-24411-00-00, and the top diaphragm 18-7842 corresponds to OEM 6E5-24471-00-00.

Does this kit include a full replacement fuel pump? No, the 18-7788 kit is a rebuild kit containing the gasket and diaphragm only, not a complete fuel pump assembly.

What size is the outlet connection on the fuel pump this kit services? The fuel pump uses a barbed outlet connection sized at 0.5 inches, paired with a hose barb inlet.

Is the fuel pump this kit services mechanical or electric? It is a mechanically operated, tank-mounted fuel pump, consistent with the 18-7788 rebuild kit's fitment.

What are the dimensions of the 18-7788 kit packaging? Item dimensions for the 18-7788 kit are 6.75 x 6 x 1 inches.

How much does the Sierra 18-7788 Fuel Pump Kit weigh? The kit weighs 0.02 pounds.

Why would I need to replace the diaphragm and gasket in my Yamaha fuel pump? Fuel pump diaphragms and gaskets harden and crack over time, which can cause fuel leaks or a loss of pump pressure; the 18-7788 kit replaces both wear parts.

Is Sierra 18-7788 a genuine Yamaha part or an aftermarket equivalent? 18-7788 is a Sierra part manufactured as an equivalent to OEM number 6E5-24411-00-00 for Yamaha V-4 and V-6 outboards, not a Yamaha-branded part.