Mercury 4-Stroke Outboard Oil Drain Screw Washer - 12-803516
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The Mercury MerCruiser Quicksilver 12-803516 is a genuine Mercury Marine OEM engine oil drain screw washer used on select small Mercury 4-stroke outboards. This washer seals the engine oil drain screw area where the factory parts diagram calls for 803516 / 12-803516, helping prevent engine oil seepage after oil changes or drain plug service.
Key Features
- Genuine Mercury Marine factory OEM washer.
- Mercury/MerCruiser part number: 12-803516.
- Manufacturer part number: 803516.
- Official part label: WASHER.
- Common retail pack references include 12-803516 1 and 12-8035161.
- GTIN/UPC: 745061268975.
- Listed shipping weight: 0.02 lb.
- Listed shipping dimensions: 1.38 in. L x 0.13 in. W x 1.38 in. H.
- Used at the engine oil drain screw location where specified by Mercury parts diagram.
Engine Compatibility
Common where-used application groups include select small Mercury 4-stroke outboards by serial number and drain screw diagram, including:
- 4 HP 4-Stroke applications where specified
- 5 HP 4-Stroke applications where specified
- 5 HP 4-Stroke JCI applications where specified
- 6 HP 4-Stroke applications where specified
Use this washer only where the Mercury parts diagram specifically calls for 12-803516 / 803516.
Serial Number Fitment Notice
Confirm fitment by outboard serial number, horsepower, oil pan/drain screw diagram, and exact drain plug hardware before ordering. Small Mercury 4-stroke outboards can use different drain screws, washers, and sealing hardware depending on production range and powerhead configuration.
When This Part Needs Replacement
Replace this washer whenever the engine oil drain screw is removed during an oil change or crankcase service. It should also be replaced if the old washer is flattened, nicked, hardened, cracked, leaking, stuck to the drain plug, or no longer seals cleanly after torque. Reusing a compressed washer can cause oil seepage around the drain screw.
Installation Notes
Clean the drain screw, washer seat, and oil pan sealing surface before installation. Confirm the old washer has been removed before fitting the new one. Install the washer in the correct drain screw location and tighten the plug according to the Mercury service manual for the specific engine. After refilling with oil, run the engine and recheck the drain plug area for seepage.
Alternate/Superseded Part Numbers
- 12-803516 — Mercury/MerCruiser formatted part number
- 803516 — Manufacturer part number
- 12-803516 1 — individual retail pack reference
- 12-8035161 — individual retail pack reference
- Tohatsu/Nissan 3H6001150 — cross-reference; verify by engine model and diagram before substitution
Parts Desk Insight
Drain screw washers are inexpensive but important service parts. Replacing the washer during each oil change helps avoid slow oil leaks from a reused crush seal, especially on small portable 4-stroke outboards where the drain plug area is exposed during seasonal service.
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.