Bottom Cowl Gasket – Fits Mercury/Mercruiser 20 HP (Replaces 27-39401)

$15.15 $24.00

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Product Details

This is a replacement Bottom Cowl Gasket designed for vintage 20 HP, 2-stroke Mercury Merc 200 outboard engines. It serves as a powerhead to mounting plate gasket, ensuring a proper seal to protect internal engine components.

It is a direct interchange for Mercury/Quicksilver part number 27-39401 and Mercury Marine 39401.

Installation Location: Bottom Cowl
Function: Seals the powerhead to the mounting plate
Material: Engineered to meet or exceed OEM specifications

Part Number Matrix

Use this matrix to confirm equivalent references across OEM and aftermarket.

Brand	Part Number
Mercury/Quicksilver	27-39401
Mercury Marine	39401

Engine & Model Compatibility

Confirm your engine model/year in the table below.

This part is compatible with specific vintage Mercury 200 models based on serial number ranges. Please verify your engine's serial number falls within the listed ranges.

Brand	Model	Rated HP	Stroke	Years	OEM Part No.	Notes
Mercury	200	20	2-Stroke	1866496-2296266	27-39401	Vintage Merc 200
Mercury	200	20	2-Stroke	2296267-2827676	27-39401	Vintage Merc 200
Mercury	200	20	2-Stroke	2827677-3226957	27-39401	Vintage Merc 200
Mercury	200	20	2-Stroke	3226958-3537530	27-39401	Vintage Merc 200
Mercury	200	20	2-Stroke	3537531-4709592	27-39401	Vintage Merc 200
Mercury	200	20	2-Stroke	4709593 & Up	27-39401	Vintage Merc 200
Mercury	200	20	2-Stroke	7012358-7098522	27-39401	Vintage Merc 200
Mercury	200	20	2-Stroke	7098523 & Up	27-39401	Vintage Merc 200
Mercury	200	20	2-Stroke	8006265-8045198	27-39401	Vintage Merc 200
Mercury	200	20	2-Stroke	8045199 & Up	27-39401	Vintage Merc 200
Mercury	200	20	2-Stroke	9016254-9157229	27-39401	Vintage Merc 200
Mercury	200	20	2-Stroke	9157230 & Up	27-39401	Vintage Merc 200

Technical Specs

Product Type: Gasket
Installation: Bottom Cowl
Dimensions: 11.63 × 8.0 × 1.13 inches
Weight: 0.03 lbs (0.014 kg)
Material: OEM Original
Other Technical Attributes: Powerhead to Mounting Plate Gasket

What’s in the Box

1 x Gasket (27-39401)

Installation Notes

Ensure the engine is off and the battery is disconnected.
Carefully remove the engine cowling to access the gasket area.
Remove the old bottom cowl gasket and any remaining adhesive or sealant.
Thoroughly clean and dry both mating surfaces. Any debris can cause a poor seal.
Position the new gasket correctly on the mounting plate.
Reinstall the powerhead and components, tightening bolts to the manufacturer's specified torque sequence and values.
Reattach the engine cowling and reconnect the battery.

Troubleshooting & FAQ

How do I know this gasket will fit my vintage Mercury?

This gasket is for very specific vintage Mercury Merc 200 models. The most reliable way to confirm fitment is by matching your engine's serial number to the ranges listed in the Engine & Model Compatibility table.

Do I need to use gasket sealant with this part?

Generally, new gaskets are designed to seal without additional sealant. However, for older engines or if mating surfaces have minor imperfections, a thin layer of marine-grade gasket sealant can be used. Always consult your engine's service manual for specific recommendations.

What are the signs of a failed bottom cowl gasket?

Signs of a faulty gasket include water intrusion into the engine compartment, visible corrosion around the seal, engine overheating, or an exhaust leak. A physical inspection showing cracks, brittleness, or compression of the old gasket also indicates it's time for a replacement.

How often should this gasket be replaced?

This gasket does not have a set replacement interval. It should be replaced whenever the powerhead is removed or if it shows any signs of wear, damage, or leakage.

Is this a genuine Mercury part?

This listing is an aftermarket replacement (not OEM). It is built to OEM-level specifications with comparable materials and manufactured in an ISO 9002 facility, with batch inspections for consistency.

What are the shipping speed & cost?

We ship worldwide quickly—typical transit is 5–15 days. Standard shipping is free; expedited options appear at checkout where available.

What is the warranty & return policy?

This part is covered by a 1-year warranty against manufacturing defects under normal use. If issues arise, contact our support with your order details. Returns are accepted within our standard window for unused items in their 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

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