Mercury / Mariner / Force Outboard Fuel Pump Rebuild Kit – Sierra 18-7817 – Replaces OEM# 21-857005A1, 21-42990A7

Restore reliable fuel delivery to your Mercury, Mariner, or Force 2-stroke outboard with the Sierra 18-7817 fuel pump rebuild kit. It includes the replacement diaphragms, gaskets, and check valve components needed to rebuild a worn or leaking diaphragm fuel pump, built to meet or exceed OEM specs. The diaphragm material is ethanol-resistant.

A tired fuel pump diaphragm can cause hard starting, bogging under load, or the engine dying at higher RPM. Rebuilding the pump is an inexpensive fix that brings fuel pressure back to spec.

Replaces OEM part numbers:

• Mercury/Mariner: 21-857005A1, 21-42990A7, 21-42990A8, 21-42990A9, 21-42990A10
• Chrysler/Force: 21-857005A1, 21-42990A8, 21-42990A9, 21-42990A10

Common applications: Many Mercury/Mariner 2-stroke 3-cylinder and V6 outboards (including 40, 90, 135–200hp models) and select Force outboards. Fitment varies by serial number; some similar-looking engines (for example, certain early-'90s Force 50hp) use a different kit.

Note: This is a rebuild kit, not a complete fuel pump. Installation instructions are not included; refer to a service manual for your engine.

For the correct fitment please send us an email to orders@hawkeyemarine.net with your engine's model and serial number.