Mercruiser Fuel Filter – Fits Mercruiser Marine Engines (Replaces 3847644)
Mercruiser Fuel Filter – Fits Mercruiser Marine Engines (Replaces 3847644) is backordered and will ship as soon as it is back in stock.
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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
Mercruiser Fuel Filter – Fits Mercruiser Marine Engines (Replaces 3...
Product Details
This water-separating Mercruiser Fuel Filter is designed for a wide range of Mercruiser marine engines from 1983 to present, including popular 3.0L, 4.3L, 5.0L, and 5.7L models. It effectively removes water and other contaminants from your fuel system, ensuring reliable engine performance and protection.
This part is a direct replacement for Mercruiser part number 3847644 and Quicksilver 35-8M0122423.
- Features a spin-on canister design for straightforward installation.
- Protects the engine by separating damaging water and debris from gasoline.
- Mounts directly to the fuel pump assembly for a secure fit.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Mercruiser | 3847644 |
| Quicksilver | 35-8M0122423 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
For Mercruiser engines, ensure you are referencing the correct part number for your model year, as later models may use an updated filter design.
| Brand | Model | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|
| Mercruiser | 3.0L | 4-Stroke | 3847644 | ||
| Mercruiser | 4.3L | 4-Stroke | 3847644 | ||
| Mercruiser | 5.0L | 4-Stroke | 3847644 | ||
| Mercruiser | 5.7L | 4-Stroke | 3847644 | ||
| Mercruiser | 4.5L | 4-Stroke | 2018+ | 35-8M0122423 | May use newer filter design |
Technical Specs
- Product Type
- Water-Separating Fuel Filter
- Installation
- Spin-on canister
- Fuel Type
- Gasoline
- Connection
- Direct mount to fuel pump
- Housing Material
- Metal canister
- Dimensions
- 13.0" L x 9.0" W x 9.0" H
- Fitting Type
- Threaded spin-on
- Other Technical Attributes
- Water-separating design to remove contaminants and water from fuel
What’s in the Box
- 1 x Fuel Filter (3847644)
Installation Notes
- Turn off the engine and allow it to cool completely. Disable the fuel supply and disconnect the battery for safety.
- Place a suitable container beneath the old filter to catch any fuel spillage.
- Using an appropriate filter wrench, turn the old canister counter-clockwise to remove it.
- Clean the mounting surface and lightly lubricate the new filter's gasket with clean engine oil.
- Spin the new filter on by hand until the gasket makes firm contact with the base.
- Tighten an additional 3/4 to 1 full turn according to manufacturer specifications. Do not overtighten.
- Restore the fuel supply and reconnect the battery.
- Prime the fuel system as required and carefully inspect for leaks before starting the engine.
Troubleshooting & FAQ
How do I know if this filter fits my engine?
This filter fits a wide range of Mercruiser engines from 1983-present, including 3.0L, 4.3L, 5.0L, and 5.7L models. Check the Part Number Matrix and Engine Compatibility table to confirm your specific model requires part number 3847644. Note that some later models, such as the 4.5L (2018+), may use the newer 35-8M0122423 filter.
What are the signs of a clogged or failing fuel filter?
Common symptoms include engine hesitation, loss of power, stalling, difficulty starting, or rough idling. These issues occur because a clogged filter restricts the flow of fuel to the engine.
How often should I change my fuel filter?
It is generally recommended to replace your water-separating fuel filter annually or every 100 hours of engine operation, whichever comes first. Always refer to your engine's service manual for the specific maintenance interval and procedure.
What is the difference between part 3847644 and 35-8M0122423?
Part number 3847644 is the standard filter for many Mercruiser engines. Part 35-8M0122423 is a newer design used on some later model engines, like the 4.5L (2018+). They may not be interchangeable; always verify the correct part for your specific engine and model year 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
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