Exhaust Gasket – Fits Mercury 650 3-Cylinder (Replaces 27-64859)
Exhaust Gasket – Fits Mercury 650 3-Cylinder (Replaces 27-64859) 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
Exhaust Gasket – Fits Mercury 650 3-Cylinder (Replaces 27-64859)
Product Details
This aftermarket Exhaust Gasket – Fits Mercury 650 3-Cylinder (Replaces 27-64859) is designed for Mercury 650 HP 3-cylinder, 2-stroke outboard engines manufactured across various model years, typically through the early 1990s. It ensures a precise seal between the exhaust plate and the exhaust manifold cover.
It serves as a direct replacement for Mercury part number 27-64859 and Mercury/Mariner/Force part 27-64859.
- Installs between the exhaust plate and manifold cover.
- Engineered for use in gasoline marine engines.
- Each package includes two gaskets for a complete service.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Mercury | 27-64859 |
| Mercury/Mariner/Force | 27-64859 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
This part is specifically for certain Mercury outboard models. Please verify your engine's serial number falls within the ranges listed for a correct fit.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Mercury | 650 (3 CYL.) | 65 | 2-Stroke | 3547987 – 4382056 | 27-64859 | Serial number range |
| Mercury | 650 (3 CYL.) | 65 | 2-Stroke | 7013633 – 7073472 | 27-64859 | Serial number range |
| Mercury | 650 (3 CYL.) | 65 | 2-Stroke | 8006640 – 8042349 | 27-64859 | Serial number range |
| Mercury | 650 (3 CYL.) | 65 | 2-Stroke | 9020074 – 9112988 | 27-64859 | Serial number range |
Technical Specs
- Product Type
- Gasket
- Application
- Mercury/Mariner/Force 65 (650) HP 3-Cylinder outboards
- Installation Location
- Plate to Exhaust Manifold Cover
- Fuel Type
- Gasoline
- Product Dimensions
- Length: 31.0, Width: 18.0, Height: 0.2
What’s in the Box
- 2 x Gasket (Replaces 27-64859)
Installation Notes
- Ensure the engine is off and has completely cooled down before beginning. Disconnect the battery for safety.
- Locate and remove the exhaust manifold cover, carefully noting the position of all fasteners.
- Remove the old gasket. Thoroughly clean the mating surfaces on both the manifold and the cover, ensuring they are free of any old material, carbon, or debris.
- Position the new gasket correctly onto the engine block or plate. Do not use any sealant unless specified by the engine manufacturer's service manual.
- Reinstall the exhaust manifold cover, hand-tightening the bolts first to ensure correct alignment.
- Tighten the bolts in the sequence and to the torque values specified in your engine's service manual.
- Reconnect the battery, start the engine, and carefully inspect for any exhaust or water leaks around the cover.
Troubleshooting & FAQ
How do I know if this gasket will fit my Mercury engine?
This gasket is designed for Mercury 650 (3 CYL.) 65 HP 2-Stroke outboards. The most reliable way to confirm fitment is to check your engine's serial number against the ranges listed in the Engine & Model Compatibility table. If your serial number falls within one of those ranges, the part is compatible.
What are the signs of a failed exhaust gasket?
Common symptoms of a bad exhaust gasket include an unusually loud exhaust noise, evidence of water or soot leaking from the exhaust manifold cover area, engine overheating, or a noticeable decrease in engine performance.
Is this listing for one gasket or a pair?
This product is sold as a package containing two gaskets, allowing for a complete replacement service.
When should this gasket be replaced?
Exhaust gaskets should be replaced any time the components they seal are removed or if you observe any signs of leakage. While there is no fixed replacement interval, they are a common wear item that should be inspected during routine maintenance.
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.
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