Mercury MerCruiser Quicksilver Water Pump Repair Kit 8M0135821
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Mercury / MerCruiser Quicksilver Water Pump Repair Kit — 8M0135821
The Mercury Quicksilver 8M0135821 is a genuine OEM complete water pump repair kit designed for select Mercury FourStroke EFI outboard engines. It includes the main components required to rebuild the water pump and restore proper cooling system performance.
Key Specifications
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Part Number: 8M0135821 (also listed as 98-8M0135821)
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Component Type: Water pump repair / service kit
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Application: Lower unit water pump assembly
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OEM Brand: Mercury Marine / Quicksilver
Compatible Engines
This kit is designed for Mercury EFI FourStroke outboards, including:
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9.9 HP EFI ProKicker (333cc)
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10 HP EFI
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15 HP EFI
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20 HP EFI
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SeaPro 10–20 HP models
Typical serial number ranges include:
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9.9 HP EFI: 1R008146 – 1R278792
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10–20 HP EFI: 0R833820 and newer
What’s Included in the Kit
The complete repair kit typically contains the major water-pump service components:
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Water pump impeller
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Water pump housing / case
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Liner (insert cup)
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Wear plate / guide plate
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Oil seal
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Gaskets
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Drive key
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Additional sealing components
These parts allow a full rebuild of the water pump assembly inside the lower unit.
Function in the Engine
The water pump circulates cooling water from the lower unit through the engine block to control temperature.
A healthy water pump ensures:
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Proper engine cooling
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Protection from overheating
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Consistent water flow through the cooling system
Common signs of water pump failure include:
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Weak or no tell-tale water stream
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Overheat alarms
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Reduced cooling efficiency.
⚠️ Service Tip:
Mercury generally recommends inspecting the impeller annually and replacing it every 100–200 hours or every 1–2 years, depending on usage and water conditions.
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.