Water Separating Fuel Filter – Fits MerCruiser 5.0L/5.7L/6.2L/8.1L/8.2L (Replaces 8M0093688, 866171A01)
Water Separating Fuel Filter – Fits MerCruiser 5.0L/5.7L/6.2L/8.1L/8.2L (Replaces 8M0093688, 866171A01) is backordered and will ship as soon as it is back in stock.
Couldn't load pickup availability
Worry-free returns
Worry-free returns
You may return most new, unopened items within 7 days of delivery for a full refund. We'll also pay the return shipping costs if the return is a result of our error (you received an incorrect or defective item, etc.).
You should expect to receive your refund within four weeks of giving your package to the return shipper, however, in many cases you will receive a refund more quickly. This time period includes the transit time for us to receive your return from the shipper (5 to 10 business days), the time it takes us to process your return once we receive it (3 to 5 business days), and the time it takes your bank to process our refund request (5 to 10 business days).
If you need to return an item, simply login to your account, view the order using the "Complete Orders" link under the My Account menu and click the Return Item(s) button. We'll notify you via e-mail of your refund once we've received and processed the returned item.
Delivery and Shipping
Delivery and Shipping
Free standard shipping on all orders under 1 KG
Water Separating Fuel Filter – Fits MerCruiser 5.0L/5.7L/6.2L/8.1L/...
Product Details
This high-efficiency Water Separating Fuel Filter is engineered for MerCruiser V8 engines including the 5.0L, 5.7L, 6.2L, 8.1L, and 8.2L models equipped with the Gen III Cool Fuel System from years 2004–2015. It ensures your engine is protected from water and contaminants, delivering clean, reliable fuel for optimal performance.
This filter serves as a direct replacement for Mercury part numbers 8M0093688, 35-866171A01, and 866171A01, and is an interchange for Sierra 18-7977.
- Installs directly into the Gen III Cool Fuel System housing.
- Features a 15-micron filtration rating for superior fuel purity.
- Complete kits typically include the required filter disk and seals for a full replacement.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number | Superseded By | Notes |
|---|---|---|---|
| Mercury | 35-866171A01 | 8M0093688 | OEM Part |
| Mercury | 866171A01 | 8M0093688 | OEM Part |
| Mercury | 8M0093688 | Current OEM Part | |
| Sierra | 18-7977 | Aftermarket Cross-Reference |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
This filter is specifically designed for MerCruiser models equipped with a Generation III Cool Fuel System.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| MerCruiser | 350 MAG MPI Alpha/Bravo | 300 | 4-Stroke | 2004–2015 | 35-8M0093688, 866171A01 | Gen III Fuel Cooler |
| MerCruiser | 350 MAG MPI Horizon Alpha/Bravo | 300 | 4-Stroke | 2004–2015 | 35-8M0093688, 866171A01 | Gen III Fuel Cooler |
| MerCruiser | 350 MAG MPI Horizon MIE | 300 | 4-Stroke | 2004–2015 | 35-8M0093688, 866171A01 | Gen III Fuel Cooler |
| MerCruiser | 350 MAG MPI MIE | 300 | 4-Stroke | 2004–2015 | 35-8M0093688, 866171A01 | Gen III Fuel Cooler |
| MerCruiser | 370 MPI | 370 | 4-Stroke | 2004–2015 | 35-8M0093688, 866171A01 | Gen III Fuel Cooler |
| MerCruiser | 496 MAG | 375 | 4-Stroke | 2004–2015 | 35-8M0093688, 866171A01 | Gen III Fuel Cooler |
| MerCruiser | 496 MAG H.O. | 425 | 4-Stroke | 2004–2015 | 35-8M0093688, 866171A01 | Gen III Fuel Cooler |
| MerCruiser | 5.0 MPI Alpha/Bravo | 260 | 4-Stroke | 2004–2015 | 35-8M0093688, 866171A01 | Gen III Fuel Cooler |
| MerCruiser | MX 6.2L MPI Alpha/Bravo | 320 | 4-Stroke | 2004–2015 | 35-8M0093688, 866171A01 | Gen III Fuel Cooler |
| MerCruiser | MX 6.2L MPI Horizon Alpha/Bravo | 320 | 4-Stroke | 2004–2015 | 35-8M0093688, 866171A01 | Gen III Fuel Cooler |
| MerCruiser | MX 6.2L MPI Horizon MIE | 320 | 4-Stroke | 2004–2015 | 35-8M0093688, 866171A01 | Gen III Fuel Cooler |
| MerCruiser | MX 6.2L MPI MIE | 320 | 4-Stroke | 2004–2015 | 35-8M0093688, 866171A01 | Gen III Fuel Cooler |
| MerCruiser | 8.1L Inboard | 375 | 4-Stroke | 2004–2015 | 35-8M0093688, 866171A01 | Gen III Fuel Cooler |
| MerCruiser | 8.1L Inboard H.O. | 420 | 4-Stroke | 2004–2015 | 35-8M0093688, 866171A01 | Gen III Fuel Cooler |
| MerCruiser | 8.2L | 380-430 | 4-Stroke | 2004–2015 | 35-8M0093688, 866171A01 | Gen III Fuel Cooler |
| MerCruiser | 5.7L MPI TOWSPORT WITH GEN III | 350 | 4-Stroke | 2004–2015 | 35-8M0093688, 866171A01 | Gen III Fuel Cooler |
| MerCruiser | 8.1L TOWSPORT (Base) | 375 | 4-Stroke | 2004–2015 | 35-8M0093688, 866171A01 | Gen III Fuel Cooler |
| MerCruiser | 8.2L Mag (Base Model) | 380 | 4-Stroke | 2004–2015 | 35-8M0093688, 866171A01 | Gen III Fuel Cooler |
| MerCruiser | 8.2L Mag (H.O. Model) | 430 | 4-Stroke | 2004–2015 | 35-8M0093688, 866171A01 | Gen III Fuel Cooler |
Technical Specs
- Product Type
- Water Separating Fuel Filter
- Installation
- In-Line, Gen III Fuel Cooler System
- Filtration Rating
- 15 micron (95% efficiency)
- Fuel Type
- Gasoline
- Connection
- Integrated into fuel cooler housing
- Housing Material
- Polyester/cellulose/glass fiber with phenolic binder coated with silicon
- Housing Color
- Yellow/white
- Fitting Type
- Direct-fit to Gen III Cool Fuel housing
- Warranty
- 1 Year (varies by manufacturer)
- Other Technical Attributes
- For Gen III Cool Fuel System only
What’s in the Box
- 1 x Fuel Filter (Replaces 8M0093688, 866171A01)
- 1 x Filter Disk (Replaces 35-892665, 8M0204703)
- 2 x Seals/Gaskets
Note: Package contents may vary by manufacturer or seller. Some packages may only include the filter element.
Installation Notes
- Disconnect the boat's battery before beginning work.
- Safely relieve pressure from the fuel system according to your engine's service manual.
- Locate the Gen III Cool Fuel module and clean the area around the top cover to prevent debris from entering.
- Carefully unscrew and remove the module's top cover.
- Remove the old fuel filter element, disk, and seals from the housing. Note their orientation.
- Clean the interior of the filter housing with a lint-free cloth.
- Lightly lubricate the new seals/gaskets with clean fuel or grease.
- Install the new filter disk, seals, and fuel filter element in the correct order.
- Reinstall the top cover and tighten it to the manufacturer’s specified torque. Do not overtighten.
- Reconnect the battery.
- Prime the fuel system as per your engine's manual and carefully check for any leaks around the housing before starting the engine.
Troubleshooting & FAQ
How do I know if this filter fits my MerCruiser engine?
This filter is specifically for MerCruiser V8 engines (5.0L, 5.7L, 6.2L, 8.1L, 8.2L) from 2004–2015 using the Gen III Cool Fuel System. To be certain, please check your engine's part manual or the number on your existing filter.
What is the difference between this filter and the older 866171A01?
The part number 8M0093688 is the official OEM supersession for 866171A01. It is the current, direct-fit replacement from Mercury and is functionally identical for all specified applications.
How often should I replace this fuel filter?
For best engine performance and protection, it is recommended to replace your water-separating fuel filter every 100 hours of operation or at least once per year, whichever comes first. Always consult your engine's service manual for specific maintenance schedules.
What are the signs of a clogged or failing fuel filter?
Common symptoms include engine hesitation, loss of power, stalling, difficulty starting, or a rough idle. If you experience these issues, a clogged fuel filter is a common cause and should be inspected immediately.
Is the filter disk included in the package?
A complete kit, as detailed in the "What’s in the Box" section, typically includes the fuel filter, a new filter disk, and the necessary seals. However, contents can vary by seller, so we advise confirming the listed contents before purchasing.
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
Payment methods
Your payment information is processed securely. We do not store credit card details nor have access to your credit card information.
