Air Filter for Mercury OptiMax V6 225HP 250HP 300HP – OEM Replacement 35-853333
This air filter is engineered for Mercury OptiMax V6 engines ranging from 115 to 300 horsepower, including DFI (Direct Fuel Injection) models from 1998 onward. It delivers reliable filtration for a wide range of OptiMax V6 configurations, ensuring consistent airflow and engine protection.
Direct replacement for Mercury OEM part numbers 35-853333 and 35-853333T, as well as Sierra part number 18-7997. This aftermarket filter is designed to meet or exceed original specifications for fit, form, and function.
- Plug-and-play installation with no assembly required
- Constructed from high-grade plastic for durability
- Tested prior to shipment for quality assurance
Part Number Cross-Reference
Use this table to confirm equivalent part numbers across OEM and aftermarket brands.
| Brand |
Part Number |
| Mercury |
35-853333 |
| Mercury |
35-853333T |
| Sierra |
18-7997 |
Compatible Engine Models
Confirm your engine model/year in the table below. For Mercury owners, here's a guide to help you identify your engine's serial/model: Mercury Serial Number Guide. You can also review exploded diagrams to verify part numbers: Mercury Parts Diagrams & Catalog.
| Brand |
Model |
Years |
| Mercury OptiMax |
V-115 DFI (2.5L) |
2000 |
| Mercury OptiMax |
V-135 DFI (2.5L) |
1998 & Up |
| Mercury OptiMax |
V-150 DFI (2.5L) |
1998 & Up |
| Mercury OptiMax |
V-175 DFI (2.5L) |
2001 & Up |
| Mercury OptiMax |
200 DFI |
1998-2002 |
| Mercury OptiMax |
225 DFI |
1998-2002 |
| Mercury OptiMax |
V6 225 |
1998 & Up |
| Mercury OptiMax |
V6 250 |
1998 & Up |
| Mercury OptiMax |
V6 300 |
1998 & Up |
Technical Specifications
| Specification |
Value |
| Color |
Blue |
| Material |
Plastic |
| Part Number |
35-853333T, 35-853333 |
| Sierra Cross-Reference |
18-7997 |
Package Contents
Installation Guide
- Disconnect the battery and ensure the engine is cool before beginning work.
- Locate the air filter housing on your Mercury OptiMax V6 engine; it is typically positioned near the intake manifold.
- Remove the retaining clips or screws securing the air filter cover.
- Carefully lift off the cover and remove the old air filter element.
- Inspect the housing interior for debris or moisture and clean if necessary.
- Position the new air filter element into the housing, ensuring it seats properly on all edges.
- Replace the cover and secure it with the original clips or screws.
- Reconnect the battery and start the engine to verify proper airflow and operation.
Troubleshooting & FAQ
Q: How do I confirm this air filter fits my Mercury OptiMax engine?
A: Cross-reference your engine's model and year with the compatibility table above. Verify your original part number is 35-853333 or 35-853333T, or consult your engine's parts diagram using the Mercury parts catalog link provided.
Q: How often should I replace the air filter on my OptiMax?
A: Mercury recommends inspecting the air filter every 100 hours of operation or annually, whichever comes first. Replace it if you notice discoloration, damage, or reduced engine performance. Saltwater and dusty environments may require more frequent replacement.
Q: What are the signs that my air filter needs replacement?
A: Common symptoms include reduced power, rough idling, difficulty starting, increased fuel consumption, or visible dirt and oil saturation on the filter element. Regular inspection helps prevent performance loss.
Q: Will this filter provide the same performance as the OEM Mercury part?
A: Yes. This aftermarket replacement is manufactured to OEM specifications using comparable materials and quality controls. It offers the same filtration efficiency and durability as the original Mercury part at a competitive price.
Q: OEM vs. Aftermarket?
A: This listing is an aftermarket replacement part (not an OEM component). We build to OEM specifications using comparable-grade materials. Production is done in an ISO9002-certified facility, and each batch is inspected for consistent performance.
Q: How fast do you ship and how much does it cost?
A: We offer fast global shipping—typically 5–15 days worldwide—and standard shipping is free. Expedited options are available at checkout depending on your location.
Q: What is your warranty and return policy?
A: This product includes a 1-year warranty against manufacturing defects under normal use. If something goes wrong, contact our support team with your order details. Returns are accepted within our standard return window (unused & in original condition); please see our policy page or reach out for instructions.
Important Notes
- Verify that the product images and specifications match your original part. If discrepancies exist—even if your model is listed—do not proceed with the purchase.
- This product is an aftermarket replacement part and is not an OEM component.
- Professional installation is recommended to ensure safety and optimal performance.
Why Choose JLM MARINE?
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Quality Assured: As a trusted manufacturer for over 20 years, we supply top marine brands globally.
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Fast Global Shipping: Free delivery worldwide in 5–15 days.
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Direct from Manufacturer: Competitive pricing without compromising quality.