Fuel Pump Diaphragm Repair Kit – Mercury / Mariner / Force 2-Stroke Outboards

Quality aftermarket fuel pump diaphragm repair kit for selected Mercury, Mariner and Force 2-stroke outboard engines fitted with the square-type fuel pump.

Designed to replace worn fuel pump diaphragm components, helping restore consistent fuel delivery, reliable starting and smooth engine operation.

Suitable for a wide range of selected 2-cylinder, 4-cylinder and 6-cylinder applications requiring Mercury fuel pump repair kit 21-42990A10.

Fitment – Mercury / Mariner / Force Outboards

Engine Configuration	Selected Horsepower Applications
2-Cylinder, 2-Stroke	30, 35, 40 HP
4-Cylinder, 2-Stroke	40, 45, 75, 100, 115, 125 HP
Inline 6-Cylinder, 2-Stroke	90, 115 HP
Other selected 2-Stroke models	50, 55, 60, 75, 90, 115, 125, 135, 140, 150, 175, 200, 225, 240, 250, 300 HP

Additional selected applications may include:

Jet-drive models
BigFoot models
EFI and DFI models
Selected Pro XS, XR2 and XS models

Important: These are broad potential applications from the supplied fitment information. Not every engine within these horsepower ranges uses the same fuel pump or diaphragm kit.

The original fuel pump design and part number must be checked before ordering.

Replaces Mercury / Mariner Part Numbers

21-42990A10
21-42990A7
21-42990A8
21-42990A9
21-857005A1

OEM references are provided for identification purposes only. Please confirm compatibility with your specific fuel pump assembly.

Product Details

Condition: New
Product: Fuel Pump Diaphragm Repair Kit
Quality: Marine-Grade Aftermarket
Application: Selected Mercury / Mariner / Force Outboards
Engine Type: 2-Stroke
Fuel Pump Type: Square-Type
Main References: 21-42990A10 / 21-857005A1

Please note: This is a fuel pump diaphragm repair kit, not a complete fuel pump assembly.

Please check the product photographs for the exact components supplied.

Important – Check Compatibility

Mercury, Mariner and Force used different fuel pump configurations across their 2-stroke engine ranges.

Before ordering, please confirm:

Engine horsepower and model
Engine serial number
Original fuel pump part number
Fuel pump shape and configuration

If the part looks the same as yours, this does not always mean it is the correct part for your outboard.

If unsure, contact SSI Marine with your engine serial number and a photograph of the existing fuel pump before purchasing.

Why Buy From SSI Marine?

Workshop-tested aftermarket and genuine parts
Over 10,000 genuine and aftermarket items stocked
Same-day dispatch before 1 PM Monday–Friday
Royal Mail Tracked 24
UK stock – collection from Leigh, Greater Manchester
Technical support from experienced marine engineers

Buyer Responsibility: Please confirm compatibility before purchasing.

30–300 HP Mercury Mariner Outboard Fuel Pump Diaphragm Kit 2-Stroke 21-42990A10