Sierra 18-7918 4-Cycle Outboard Oil Filter – Mercury Verado Inline-6
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The Sierra 18-7918 is a spin-on oil filter built specifically for Mercury Verado inline-6 four-stroke outboards. It’s engineered with a heavy-wall steel canister, epoxy-coated exterior for corrosion resistance, and high-efficiency filter media to match or exceed Mercury’s original equipment filtration requirements. The 24 mm × 1.5 thread and integrated anti-drainback valve are spec’d directly to the Verado inline-6 oil system — keeping oil where it belongs at shutdown and ensuring clean oil circulation from the first moment you fire up in the morning.
Fitment note: Mercury uses different oil filters across the Verado inline-4, inline-6, and newer V6/V8 outboard families. Confirm your engine’s horsepower, model, and serial number match the Verado inline-6 application range below before ordering. If your existing filter carries a different OEM part number, cross-reference it against the list below.
Compatible Applications
- Mercury Verado Inline-6 — 200 HP
- Mercury Verado Inline-6 — 225 HP
- Mercury Verado Inline-6 — 250 HP
- Mercury Verado Inline-6 — 275 HP
- Mercury Verado Inline-6 — 300 HP
- Mercury Verado Inline-6 — 350 HP
- Mercury Verado Inline-6 — 400R HP
- Serial number fitment begins with early 2005 production — verify your engine serial number before ordering
- Not compatible with Verado inline-4, V6, or V8 outboard families — those engines use different filter specifications
Part Information
- Sierra part number: 18-7918
- SKU: 47-7918
- Brand: Sierra International
- Filter type: Spin-on oil filter
- Thread size: 24 mm × 1.5
- Construction: Heavy-wall steel canister, epoxy-coated exterior
- Anti-drainback valve: Yes
- Filtration standard: Meets or exceeds OEM filtration requirements
- UPC: 808282199517
- Condition: New
OEM Cross-Reference Numbers
- Sierra: 18-7918
- Mercury Marine: 35-877769K01
- Mercury Marine: 35-883701K01
- Quicksilver: 35-877769Q01
- Mallory: 9-57816
- Mallory: 9-57823
Service Interval
- Replace at every oil change — spin-on oil filters cannot be cleaned or reused
- Mercury Verado outboard oil change interval: every 100 hours of operation or once per season, whichever comes first — confirm against your engine’s service manual
- Always replace the filter when changing oil — leaving the old filter with fresh oil immediately contaminates it
- Run the engine after installation and inspect the filter area for leaks before returning to service
Installation Notes
- Remove the old filter and confirm its sealing gasket has not remained on the engine mounting surface — a double-gasketed filter will not seal and will leak under pressure
- Lightly lubricate the new filter’s gasket with clean engine oil before installation
- Hand-tight plus 3/4 turn — do not use a filter wrench to tighten; the rubber gasket creates the seal, not torque
- Install per Mercury’s service instructions for your Verado model
Technical FAQ
Q: How do I quickly identify this is the right filter for my Verado?
The fastest check is the thread spec: 24 mm × 1.5. Then cross-reference the OEM number on your existing filter against the list above — if it shows Mercury 35-877769K01, 35-883701K01, or Quicksilver 35-877769Q01, the Sierra 18-7918 is the correct replacement.
Q: Will this filter work on my Verado V6 or V8?
No. Mercury’s newer V6 and V8 Verado platforms use different oil filter specifications. The 18-7918 is specific to the Verado inline-6 family. Check your engine’s service manual or the OEM filter number currently installed to confirm.
Q: Can I use this filter on a non-Mercury outboard?
Only if the engine’s service data specifies the same thread size, bypass valve pressure, and anti-drainback valve design. Do not substitute based on physical appearance alone — always verify against your engine’s service manual or OEM filter cross-reference.
Q: Does this filter come with a new sealing gasket?
Yes — the gasket is integrated into the filter base. Always check that the old gasket is fully off the engine before installing the new filter.
Complete the Service — Related Products
- Sierra 9231 Complete Oil Change Kit – 4-Stroke Outboard — filter + drain plug gasket bundled for one-stop service ordering
Other Sierra 4-Cycle Outboard Oil Filters
- Sierra 18-7896 4-Cycle Outboard Oil Filter
- Sierra 18-7897 4-Cycle Outboard Oil Filter
- Sierra 18-7901 4-Cycle Outboard Oil Filter
- Sierra 18-7902 4-Cycle Outboard Oil Filter
- Sierra 18-7903 4-Cycle Outboard Oil Filter
- Sierra 18-7909 4-Cycle Outboard Oil Filter
- Sierra 18-7913 4-Cycle Outboard Oil Filter
- Sierra 18-7914 4-Cycle Outboard Oil Filter
- Sierra 18-7916 4-Cycle Outboard Oil Filter
- Sierra 18-79062 4-Cycle Outboard Oil Filter
- Sierra 18-79111 4-Cycle Outboard Oil Filter
- Sierra 18-79151 4-Cycle Outboard Oil Filter
- Sierra 18-8700 4-Cycle Outboard Oil Filter
- Sierra 18-8870 4-Cycle Outboard Oil Filter
- Sierra 18-57824 Marine Oil Filter
- Sierra 18-78242 Oil Filter – GM/Chev Short
- Sierra 18-8779 Marine Oil Filter
Parts Desk Insights
The quickest way to confirm this is the right filter is the thread spec — 24 mm × 1.5 — combined with the Mercury OEM cross-references. The 18-7918 is the standard Sierra filter for the Verado inline-6 family across the full 200–400R horsepower range, and it’s one of the more reliable fitment identifications in the Mercury outboard filter catalog because the Verado inline-6 platform has been consistent in its oil filter spec across most of its production run. The most common issue we see is customers ordering this filter for a newer Verado V6 or V8 — Mercury’s V-configuration Verado engines use a different filter, so if your motor is a newer platform, check the OEM filter number on the engine before ordering. If you have the old filter in hand, the number stamped on it will be your fastest confirmation: Mercury 35-877769K01 or 35-883701K01 means the 18-7918 is your correct Sierra replacement. Best used as a like-for-like replacement at every scheduled oil change — pair it with the Sierra 9231 Oil Change Kit if you want the drain plug gasket included in the same order.
Shipping information
In-stock and OEM parts: ship same or next business day.
Locally warehoused items: ship within 1-3 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.