Mercury Fuel Pump Diaphragm 89031A3 (Pack of 2)
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Mercury 89031A3 is a genuine OEM fuel pump diaphragm kit for select Mercury and Mariner outboard applications. Mercury parts sources identify it as DIAPHRAGM ASSEMBLY, while other OEM-oriented catalogs list it as DIAPHRAGM @2, supporting that this package is a pack of 2 diaphragms rather than a single piece.
Key Features
- Genuine Mercury / Quicksilver part number 89031A3
- Fuel pump diaphragm kit / diaphragm assembly
- Commonly sold as 2 diaphragms per kit
- Used in select older Mercury and Mariner inline 6-cylinder fuel pump applications
- Best matched by exact part number, engine model, and serial number
Engine Compatibility
The strongest application trail links 89031A3 to older Mercury/Mariner inline 6-cylinder outboards, especially 90 HP, 115 HP, and 140 HP models. One marine parts source also describes it for inline-6 engines using side bowl carburetors, which is a useful fitment clue for older fuel-system service work.
Serial Number Fitment Notice
Please confirm fitment by engine model and serial number before ordering. This is especially important for older carbureted Mercury fuel systems, where diaphragm and pump-kit details can vary by engine family and production range.
When This Part Needs Replacement
Replace these diaphragms when the fuel pump is leaking, stiff, cracked, brittle, fuel-starved, or no longer delivering consistent fuel flow. They are also a smart replacement item during fuel pump rebuild service on older inline-6 outboards. This guidance follows the part’s role in the mechanical fuel pump.
Installation Notes
Install only on the correct Mercury application and verify the existing pump setup against the part number, engine model, serial number, and carburetor/fuel pump style before ordering. Matching the original diaphragm kit exactly is the safest approach.
Alternate / Superseded Part Numbers
- 89031A3
- Related / replacement references commonly shown: 66599A3
Parts Desk Insight
The clearest verified takeaway is that 89031A3 is a Mercury fuel pump diaphragm kit for older inline-6 outboards, packaged as a pair. For Marisol Marine, the safest sale is against the exact serial number and fuel pump configuration, especially on classic 90/115/140 HP applications.
Shipping: Ships same or next day for fast Canada wide shipping. ⚓
Shipping information
In-stock and OEM parts: ship same or next business day.
Locally warehoused items: ship within 3–4 business days.
Special-order items: timeline confirmed after order.
Returns & warranty
Returns & Satisfaction Guarantee
We stand firmly behind the quality of every product we sell. Your confidence matters to us — and we back it with a straightforward 30-Day Satisfaction Guarantee.
If you are not fully satisfied, you may request a return within 30 days of delivery. All returns must receive pre-approval prior to being sent back. Unauthorized returns will not be accepted.
To qualify for a return:
Item must be in new, unused condition
Product must be in its original packaging
All parts, components, hardware, manuals, and accessories must be included
Packaging must be undamaged and suitable for resale
Important:
Electronics are strictly inspected. No returns on open-box electronics. Exceptions may apply only with prior written approval. Any electronic unit that has been installed, powered, activated, or altered may not be eligible for return.
We are serious about product integrity — and equally serious about taking care of our customers. If there is ever a product issue, contact us immediately so we can make it right.
For return authorization, please contact our support team before shipping anything back.