Mercury MerCruiser Quicksilver Water Pump Cover-to-Face-Plate Gasket 43033
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Water Pump Cover-to-Face-Plate Gasket — OEM Reference 43033 / 27-43033
Part Number: 43033 | Service format: 27-43033
Brand: Mercury Marine / Quicksilver
Official Product Type: Water Pump Gasket — Cover to Face Plate
Supersedes: 43033 / 27-43033
Replaced By: 430331 / 27-430331
System: Cooling — Lower-Unit Water Pump Assembly
Diagram Position: Between water pump cover and face plate, upper portion of the impeller housing stack
What This Gasket Does
This genuine Mercury Marine / Quicksilver gasket seals the joint between the water pump cover and the face plate in select Mercury, Mariner, Force, and MerCruiser lower-unit water pump assemblies. The opening pattern and thickness are matched to the specific water pump cover and face plate so that all cooling-water passages seal correctly. A generic flat gasket or similar-looking substitute can alter pump clearances or leave part of a water passage improperly sealed.
Compatible Applications
Fitment depends on engine model, drive model, gear housing, and serial number. Verify against your Mercury or MerCruiser parts diagram before ordering.
- Mercury / Mariner 70, 75, 80, and 90 HP 3-cylinder outboards
- Selected Mercury / Mariner 50 HP EFI 4-stroke gearcases
- Selected Mercury / Mariner 115 HP 4-cylinder 2-stroke gearcases
- Broader Mercury / Mariner 45 Jet, 50–300 HP, Verado, DFI, EFI, and 4-stroke model families (serial-number dependent)
- MerCruiser Alpha One Gen II — 1991–1997 and 1998-and-up serial ranges
- Selected Force and additional MerCruiser drive applications (verify by serial number)
Serial Number Fitment Notice
Mercury uses several similar gaskets within the same water pump stack — including separate gaskets below the face plate. Always confirm your parts diagram specifically calls for 43033 / 430331 at the cover-to-face-plate position before ordering. Use your engine serial number to verify fitment.
When to Replace This Gasket
Replace whenever the water pump cover or face plate is removed for impeller or full pump service. A compressed, torn, hardened, or misaligned gasket can allow leakage within the pump housing and reduce cooling-water delivery to the engine.
Service Interval
Replace at every impeller service — typically every 2–3 years or 300 hours, or whenever the water pump cover or face plate is disturbed.
Installation Notes
- Clean both mating surfaces and remove all old gasket material without gouging the face plate or pump cover.
- Inspect the impeller, face plate, housing, seals, and adjacent gaskets while the assembly is apart.
- Install the new gasket in the same orientation shown in your Mercury or MerCruiser parts diagram.
- Replace related water pump wear parts (impeller, face plate, housing, seals) if they show grooves, corrosion, or heat damage.
Dimensions (27-430331 current replacement reference)
Approximately 7.50 in. × 5.25 in. × 0.25 in. | Weight: approx. 0.03 lb (0.02 kg)
Alternate and Superseded Part Numbers
- Original: 43033 / 27-43033
- Current OEM replacement: 430331 / 27-430331
- Aftermarket cross-reference: Sierra 18-2564
- Related interchange: AM27-430331, Honda 19234-ZW1-003, OMC / Johnson / Evinrude 0509257
The current replacement (430331) may differ visually from the original while serving the same sealing function.
Kit Contents
Single gasket. Not a kit. Order additional water pump components separately if performing a complete pump service.
Related Parts
- Water pump impeller — verify by serial number
- Water pump face plate — verify by serial number
- Water pump housing — verify by serial number
- Lower water pump gaskets — verify separate positions in diagram
- Mercury MerCruiser Lower Gasket 8M0142616
Parts Desk Insights
This gasket is most commonly ordered during a full impeller service when the pump cover is already removed — it is not a standalone emergency part. The key detail customers miss is that the 43033 reference has been superseded by 430331, and the new part may look different while functioning identically. Because Mercury uses multiple similar gaskets in the same pump stack, confirm the diagram position (cover-to-face-plate) before ordering to avoid receiving the wrong gasket. Customers who order this part in isolation without replacing the impeller and face plate often return for a second service soon after — a complete water pump kit is typically the better value for anyone with the pump open.
Technical FAQ
Q: Can I reuse the old gasket?
No. Once compressed and disturbed, gaskets do not re-seal reliably. Always replace with a new gasket.
Q: Is 430331 the same gasket as 43033?
Yes — 430331 is the current OEM replacement for 43033. It may look slightly different but performs the same sealing function.
Q: Do I need a specific gasket for my serial number?
Yes. Mercury uses several gaskets in the same pump stack. Confirm the cover-to-face-plate position in your parts diagram and verify by serial number before ordering.
Shipping information
In-stock and OEM parts: ship same or next business day.
Locally warehoused items: ship within 1-3 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.