Air Filter – Fits Mercury Mariner 2.5L DFI 115-225 HP (Replaces 35-853333T, 18-7997)
Air Filter – Fits Mercury Mariner 2.5L DFI 115-225 HP (Replaces 35-853333T, 18-7997) is backordered and will ship as soon as it is back in stock.
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Worry-free returns
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Delivery and Shipping
Delivery and Shipping
Free standard shipping on all orders under 1 KG
Air Filter – Fits Mercury Mariner 2.5L DFI 115-225 HP (Replaces 35-...
Product Details
This high-quality Air Filter – Fits Mercury Mariner Outboard 2.5L DFI 115-225 HP is a direct-fit replacement for Mercury Mariner 2.5L DFI V6 OptiMax engines, primarily from mid-2000s model years. It ensures your engine receives clean, unrestricted airflow for optimal performance and fuel efficiency.
It serves as a direct interchange for Mercury Marine part numbers 35-853333T and 35-853333, as well as Sierra 18-7997 and other aftermarket equivalents.
- Designed as a drop-in replacement that fits the factory air box perfectly.
- Engineered specifically for Direct Fuel Injection (DFI) engine requirements.
- Helps protect internal engine components from dust, debris, and water ingestion.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Mercury Marine | 35-853333T |
| Mercury Marine | 35-853333 |
| Sierra | 18-7997 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
This air filter is designed for Mercury and Mariner 2.5L DFI V6 outboard models, including the OptiMax and SportJet series.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Mercury | OptiMax 2.5L DFI | 115 | 2-Stroke | 35-853333T | V6 engine | |
| Mercury | OptiMax 2.5L DFI | 135 | 2-Stroke | 35-853333T | V6 engine | |
| Mercury | OptiMax 2.5L DFI | 150 | 2-Stroke | 35-853333T | V6 engine | |
| Mercury | OptiMax 2.5L DFI | 175 | 2-Stroke | 35-853333T | V6 engine | |
| Mercury | OptiMax 2.5L DFI | 200 | 2-Stroke | 35-853333T | V6 engine | |
| Mercury | OptiMax 2.5L DFI | 225 | 2-Stroke | 35-853333T | V6 engine | |
| Mercury | SportJet 200DFI | 200 | 2-Stroke | 2000 & Up | 35-853333T | As noted by HIFROM |
Technical Specs
- Product Type
- Air Filter
- Installation
- Direct replacement
- Fuel Type
- Gasoline
- Connection
- Direct fit to air box
- Housing Color
- White
- Fitting Type
- Drop-in replacement
- Compatible Engines
- For DFI (Direct Fuel Injection) engines
What’s in the Box
- 1 x Air Filter (Replaces OEM 35-853333T)
Installation Notes
- Ensure the engine is off and cool to the touch. Disconnect the battery for safety.
- Locate the air filter housing, which is typically a black plastic box on the front or side of the engine.
- Release the clips or remove the screws securing the airbox cover and lift it off.
- Remove the old air filter, noting its orientation. Clean any debris from inside the housing.
- Insert the new air filter, ensuring it is seated correctly and forms a tight seal.
- Replace the airbox cover and re-secure the clips or screws. Do not overtighten.
- Reconnect the battery. The installation is now complete.
Troubleshooting & FAQ
How do I confirm this air filter fits my Mercury engine?
Verify your engine is a 2.5L DFI V6 OptiMax or 200DFI SportJet model between 115-225 HP. The most reliable method is to cross-reference your existing filter’s part number with OEM number 35-853333T or Sierra number 18-7997, as listed in our compatibility tables.
What are the signs of a clogged air filter on my outboard?
Common symptoms include a loss of power, reduced top-end RPM, increased fuel consumption, rough idling, or difficulty starting. A visual inspection will also show dirt and debris embedded in the filter media.
How often should I replace this filter?
Replacement frequency depends on operating conditions. We recommend a visual inspection every 50 hours or annually. Replace the filter whenever it appears dirty, clogged, or damaged to maintain engine health and performance.
Is any special tool needed for installation?
Typically, no special tools are required. Installation usually involves releasing clips or removing common screws (often Phillips or hex-head) on the airbox cover. The filter itself drops into place without tools.
What is the difference between this and a genuine Mercury part?
This is an aftermarket part designed to meet or exceed OEM specifications for fit, filtration, and airflow. It offers comparable performance and protection at a better value. The primary difference is the manufacturer.
Why is a specific filter needed for DFI engines?
Direct Fuel Injection (DFI) engines like the Mercury OptiMax rely on precise air-to-fuel ratios for efficiency and power. This filter is engineered to provide the consistent, clean airflow required for the engine's computer to manage combustion correctly.
OEM vs. Aftermarket?
This listing is an aftermarket replacement (not OEM). Built to OEM-level specifications with comparable materials. Manufactured in an ISO 9002 facility, batch-inspected for consistency.
Shipping speed & cost
We ship worldwide quickly—typical transit 5–15 days. Standard shipping is free; expedited options appear at checkout where available.
Warranty & returns
Covered by a 1-year warranty against manufacturing defects under normal use. If issues arise, contact support with your order details. Returns are accepted within our standard window (unused & in original condition). See our policy page or reach out for instructions.
Safety & Important Info
- Verify images/specifications vs your original part. If anything differs—even if your model appears compatible—do not purchase.
- This is an aftermarket replacement, not an OEM component.
- Professional installation is recommended for safety and performance.
About Sea Sierra
- Pro-Grade Standards — We supply marine parts engineered to OEM-level tolerances and tested for real-world conditions.
- Fast Global Fulfillment — Free standard delivery to most regions in 5–15 days.
- Manufacturer-Direct Value — Fair pricing without compromising on materials or QC.
Payment & Security
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