Mercury MerCruiser Blue Seal 8M0187157
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Mercury MerCruiser / Quicksilver Blue Seal – OEM Part 8M0187157
Prevent gear-lube leaks during maintenance with the genuine Mercury Marine / Quicksilver 8M0187157 Blue Seal. This OEM drain/fill screw gasket is installed on the gear-case drain and vent screws, creating a tight seal that prevents gear oil leaks and water intrusion in the lower unit.
Manufactured to Mercury Marine’s original equipment specifications, this small but critical seal ensures proper sealing when servicing sterndrives or outboard gearcases.
Key Features
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Genuine Mercury / Quicksilver OEM blue drain screw seal
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Creates a leak-free seal on gearcase drain and vent screws
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Prevents gear lube leaks and water intrusion
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Designed for 3/8-16 drain/fill screws
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Easy replacement during routine gear-lube service
Part Details
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OEM Part Number: 8M0187157
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Also referenced as 12-8M0187157 or 12-19183-3
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Product Type: Gearcase drain screw gasket / seal
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Material: Soft compressible sealing washer (blue)
Compatible Mercury / MerCruiser Applications
Commonly used on:
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MerCruiser sterndrive gearcases
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Mercury and Mariner outboard lower units (except some Japanese-built models and certain Verado engines)
These seals fit engines ranging from approximately 6 HP to 220 HP, depending on the drive and gearcase configuration.
Service Recommendation
Mercury recommends replacing the drain screw seal every time the gear lube is changed to ensure a proper seal and prevent leaks.
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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.