PRODUCT DETAILS
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:
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Jet-drive models
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BigFoot models
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EFI and DFI models
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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
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21-42990A10
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21-42990A7
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21-42990A8
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21-42990A9
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21-857005A1
OEM references are provided for identification purposes only. Please confirm compatibility with your specific fuel pump assembly.
Product Details
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Condition: New
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Product: Fuel Pump Diaphragm Repair Kit
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Quality: Marine-Grade Aftermarket
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Application: Selected Mercury / Mariner / Force Outboards
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Engine Type: 2-Stroke
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Fuel Pump Type: Square-Type
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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:
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Engine horsepower and model
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Engine serial number
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Original fuel pump part number
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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?
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Workshop-tested aftermarket and genuine parts
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Over 10,000 genuine and aftermarket items stocked
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Same-day dispatch before 1 PM Monday–Friday
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Royal Mail Tracked 24
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UK stock – collection from Leigh, Greater Manchester
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Technical support from experienced marine engineers
Buyer Responsibility: Please confirm compatibility before purchasing.
SHIPPING & DELIVERY
Delivery & Returns Policy
Delivery
Standard Delivery
- £7: Royal Mail Tracked 24 Service
- £3.99: Large Letter - Royal Mail 1st Class Post (Untracked)
We offer free delivery on all orders over £150 (excludes outboard engines).
Orders placed before 1:00 PM (Monday-Friday) are usually dispatched the same working day.
Most parcels are delivered within 24 hours, but please allow extra time for courier delays that may occur outside our control.
For outboard engines, please contact us for a delivery quote.
Important: Please ensure your shipping address is correct before completing checkout. SSI Marine is not responsible for parcels sent to an incorrect address provided by the buyer.
Tracking Your Order
Once your order has been dispatched, you will receive a tracking number via email (after 5 PM on the day of dispatch).
Tracking is available only for parcels sent via Royal Mail Tracked 24.
Large Letter orders are sent via Royal Mail 1st Class Post (untracked).
Returns
We accept returns of unused and undamaged items within 30 days of purchase.
Returned items must be in sellable condition and include the original packaging.
Please do not tape, label, or write directly on the product's original box.
Important: Do not return items in their original product boxes only, they must be placed inside a protective outer box or bag. Parcels returned like the example below will be subject to a 20% restocking fee.
Return shipping costs are the customer's responsibility.
Please include your order details and reason for return inside the parcel.
Refunds
Refunds are issued for the item purchase price only (shipping costs are non-refundable).
All refunds will be made using the same payment method as your original order.
Items returned in poor condition or without proper packaging may incur a 20% restocking fee.
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