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Sierra Marine Water Pump Component
Yamaha 90-300HP & Mercury FourStroke Water Pump Washer
The Sierra 18-90201 Water Pump Washer is a direct replacement for Yamaha OEM 90201-22M01-00 and Mercury OEM 8556822. This washer is used within the lower unit water pump assembly and serves as a critical spacing component between water pump components and the driveshaft assembly.
Commonly replaced during impeller service, water pump rebuilds, and lower unit maintenance, this washer is used across a large range of Yamaha F-Series, VF-Series, VMAX, OX66, HPDI, Saltwater Series, and Mercury FourStroke outboards.
Compatible Applications
Yamaha OEM 90201-22M01-00 is used on a wide range of Yamaha outboards from 90HP through 300HP. Mercury OEM 8556822 cross references to the same washer used on Mercury FourStroke applications derived from Yamaha platforms.
| Engine Family | Common Applications |
|---|---|
| Yamaha F-Series | F90, F115, F150, F175, F200, F225, F250, F300 |
| Yamaha VF-Series SHO | VF90, VF115, VF150, VF175, VF200, VF225, VF250 |
| Yamaha VMAX | 150HP, 175HP, 200HP, 225HP, 250HP, 300HP |
| Yamaha OX66 | 150HP, 200HP, 225HP, 250HP |
| Yamaha HPDI | 150HP, 200HP, 225HP, 250HP, 300HP |
| Yamaha Saltwater Series | Various 115HP-250HP Applications |
| Mercury FourStroke | 225 EFI FourStroke, 250 EFI FourStroke |
Yamaha used multiple water pump assemblies across different model years and gearcase designs. Always verify your OEM part number before ordering.
This washer replaces Yamaha OEM 90201-22M01-00 and Mercury OEM 8556822.
OEM & Cross Reference Numbers
| Type | Part Number |
|---|---|
| Sierra | 18-90201 |
| Yamaha OEM | 90201-22M01-00 |
| Mercury OEM | 8556822 |
| Mercury OEM | 12-8556822 |
| GLM | 90201GM |
Alternative Brand Available
GLM 90201GM Water Pump Washer
We also stock the GLM 90201GM version of this water pump washer. It replaces the same Yamaha and Mercury OEM numbers and fits the same applications.
What This Part Is Used For
This washer is installed within the water pump assembly and functions as a spacing and load-distribution component. Proper washer thickness and placement are important for maintaining correct water pump assembly geometry and component alignment.
During water pump service, technicians commonly inspect and replace washers, spacers, wear plates, impellers, housings, and seals together to help restore cooling system performance.
Why Replace a Water Pump Washer?
- Prevents excessive wear on water pump components
- Maintains proper spacing within the water pump assembly
- Helps ensure correct impeller and housing alignment
- Recommended during major water pump rebuilds
- Inexpensive preventative maintenance item
Sierra 18-90201 Features
- Direct replacement for Yamaha 90201-22M01-00
- Direct replacement for Mercury 8556822
- Fits Yamaha F90-F300 applications
- Fits Yamaha VF-Series SHO models
- Fits Yamaha VMAX, OX66, HPDI, and Saltwater Series engines
- Compatible with Mercury 225 and 250 EFI FourStroke models
- Quality Sierra Marine aftermarket replacement
FAQ
What OEM numbers does Sierra 18-90201 replace?
Yamaha 90201-22M01-00 and Mercury 8556822.
What Yamaha engines use this washer?
Common applications include Yamaha F90-F300, VF-Series SHO, VMAX, HPDI, OX66, and Saltwater Series outboards.
Does this fit Mercury outboards?
Yes. Mercury OEM 8556822 is commonly used on Mercury 225 and 250 EFI FourStroke applications.
Should this washer be replaced during impeller service?
It should always be inspected and replaced if wear, scoring, corrosion, or damage is present.
Do you carry another brand?
Yes. We also stock the GLM 90201GM version linked above.
Dealer Discounts & Store Policies
Dealer / Marine Industry Discounts
Are you a marine dealer, technician, boat builder, or industry professional? We offer dealer pricing for qualified marine businesses.
Shipping Policy
- Free shipping on orders over $100 continental U.S.
- Orders ship via UPS, USPS, and FedEx.
- Orders received before 5:30 PM EST ship the same business day.
- Typical delivery time is 1-5 business days.
30-Day Return Policy
- Returns accepted within 30 days of delivery.
- Parts must be new, unused, and in original packaging.
- Installed parts are not returnable.
- Return authorization required before return.
Searchable Terms
Sierra 18-90201, 18-90201, Yamaha 90201-22M01-00, Mercury 8556822, Mercury 12-8556822, water pump washer, driveshaft washer, Yamaha F250 water pump parts, Yamaha F300 water pump parts, Yamaha SHO water pump parts, Yamaha VMAX water pump washer, Yamaha OX66 water pump washer, Yamaha HPDI water pump washer, Mercury FourStroke water pump parts, GLM 90201GM
8556822
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