Mercury MerCruiser Quicksilver O-Ring 8M0204683

Mercury MerCruiser Quicksilver O-Ring – 8M0204683

Part Number: 8M0204683
Brand: Mercury Marine / Quicksilver (OEM)
Type: O-Ring
Diagram Position: Position 10

Genuine Mercury Marine OEM o-ring used in selected Mercury and MerCruiser assemblies. Mercury parts diagrams identify this component at diagram position 10. O-rings in marine applications provide critical fluid and pressure seals — using the correct OEM part ensures material compatibility and proper sealing performance in saltwater and freshwater environments.

Compatible Applications

• Selected Mercury Marine and MerCruiser assemblies where part number 8M0204683 appears at diagram position 10
• Exact fitment must be confirmed against the correct model and serial-number parts diagram

System

Sealing / gasket interface — provides an o-ring seal at diagram position 10 within the applicable Mercury assembly. Refer to the official Mercury parts diagram for your model and serial number to confirm exact location and system.

When to Replace

• O-ring is cracked, flattened, swollen, or shows any sign of deformation
• Fluid seepage or weeping is present at the sealed joint
• Any time the surrounding assembly is disassembled for service

Service Interval

Inspect at every relevant assembly service. O-rings are low-cost consumables — best practice is to replace whenever the assembly is opened rather than reusing a compressed or aged ring.

Installation Notes

• Clean the mating groove and surface thoroughly before installing
• Lightly lubricate the o-ring with a compatible marine grease or o-ring lubricant before fitting
• Do not stretch or twist the o-ring during installation
• Confirm position against the Mercury parts diagram for your specific model and serial number
• Match by part number — o-rings of similar appearance vary in material compound and dimensional tolerance

Related Parts

• Mercury MerCruiser O-Ring 8M0204684
• Mercury MerCruiser Quicksilver O-Ring 8M0204645
• Mercury MerCruiser Quicksilver O-Ring Kit 8M0164166
• Mercury MerCruiser O-Ring 25-34821
• Mercury MerCruiser O-Ring 25-8M0204654
• Mercury Quicksilver Oil Filter Adaptor O-Ring 25-33756
• Mercury MerCruiser Quicksilver Sealing Washer 8M0214950

Technical FAQ

Q: Can I substitute a generic o-ring of the same size?
A: Not recommended. Marine o-rings are compound-specific for fuel, oil, or coolant compatibility. An incorrect compound can swell, harden, or fail prematurely. Use the OEM part number to ensure the correct material.

Q: How do I confirm this is the right o-ring for my assembly?
A: Locate part number 8M0204683 at diagram position 10 in the official Mercury parts diagram for your specific model and serial number.

Q: Should I replace this o-ring during a routine service?
A: Yes — o-rings are inexpensive and should be replaced any time the assembly is opened. Reusing a compressed or aged o-ring risks a seal failure after reassembly.

Genuine Mercury Marine / Quicksilver OEM part. Match by part number and diagram position for correct fitment.

Parts Desk Insights

Best use case: This o-ring is the right choice for any Mercury or MerCruiser assembly service where part number 8M0204683 appears at diagram position 10. It is a consumable seal — always replace it when the assembly is opened, even if the old o-ring looks intact. A reused o-ring that has been compressed or heat-cycled is a common source of post-service leaks.

Most common mistake: Ordering by size rather than part number. O-rings that appear dimensionally identical can differ in rubber compound — and the wrong compound in a fuel, oil, or coolant environment will swell or degrade, causing the seal to fail. Always order by Mercury part number.

Fitment guidance: Verify 8M0204683 at diagram position 10 in the Mercury parts diagram for your specific model and serial number before ordering. If you are servicing a multi-o-ring assembly, check whether sibling part 8M0204684 is also required — assemblies often use more than one o-ring size at different positions.