Mercury Marine Gasket – Fits Mercury/Mariner 70-90 HP 3-Cylinder Outboards

$19.99

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Product Details

This is a quality aftermarket Mercury Marine Gasket – Fits Mercury/Mariner 70-90 HP 3-Cylinder Outboards (27-43004009). It is designed for use on Mercury/Mariner 70-90 HP 3-cylinder outboards, including 65 Jet models. This gasket creates a seal between the reed valve and the induction manifold.

This component is a direct replacement for OEM part numbers 27-430041, 27-430042, 27-430043, 27-430045, 27-430047, and the current 27-43004009.

Installs in the engine’s induction system.
Engineered to meet or exceed OEM specifications for a reliable seal.
Package includes one gasket.

Part Number Matrix

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

Brand	Part Number	Superseded By	Notes
Mercury	27-430041	27-43004009	Superseded Part
Mercury	27-430042	27-43004009	Superseded Part
Mercury	27-430043	27-43004009	Superseded Part
Mercury	27-430045	27-43004009	Superseded Part
Mercury	27-430047	27-43004009	Superseded Part

Engine & Model Compatibility

Confirm your engine model/year in the table below.

Fits various 3-cylinder outboards from Mercury and Mariner.

Brand	Model	Rated HP	OEM Part No.	Notes
Mercury	70 HP	70	27-43004009	Previously 27-430041/27-430042/27-430043/27-430045/27-430047
Mercury	65 Jet	65	27-43004009	Previously 27-430041/27-430042/27-430043/27-430045/27-430047
Mariner	75 HP	75	27-43004009	Previously 27-430041/27-430042/27-430043/27-430045/27-430047
Mariner	80 HP	80	27-43004009	Previously 27-430041/27-430042/27-430043/27-430045/27-430047
Mariner	90 HP	90	27-43004009	Previously 27-430041/27-430042/27-430043/27-430045/27-430047

Technical Specs

Product Type: Reed Valve Gasket
Installation: Induction System
Dimensions: 44.0 × 19.5 × 0.3 cm (17.3 × 7.7 × 0.12 in)
Weight: 0.023 kg (0.05 lb)
Compatibility: Mercury/Mariner 70-90 HP 3-cylinder outboards and 65 Jet models
OEM Part Number: 27-43004009
GTIN/UPC: 745061717404

What’s in the Box

1 x Gasket (27-43004009)

Installation Notes

Disconnect the battery and ensure the engine is cool.
Locate and remove the induction manifold cover to access the reed valve assembly.
Carefully remove the old gasket, taking note of its orientation.
Thoroughly clean both mating surfaces to remove any old gasket material or residue.
Position the new gasket correctly onto the reed valve block.
Reinstall the induction manifold and tighten bolts to the manufacturer's specified torque.
Reconnect the battery and test the engine for proper operation and leaks.

Troubleshooting & FAQ

Which engines does this gasket fit?

This gasket is designed specifically for Mercury and Mariner 70, 75, 80, and 90 HP 3-cylinder outboard engines, as well as 65 Jet models.

Where is this gasket installed on the engine?

It is installed between the reed valve assembly and the induction manifold, providing a critical seal for proper air and fuel mixture.

What are the signs of a failed reed valve gasket?

Symptoms of a faulty gasket can include poor or rough idling, a noticeable loss of engine power, difficulty starting, backfiring through the intake, or visible fuel leakage around the manifold area.

Is this part the same as Mercury part 27-430042?

Yes, this part (27-43004009) is the direct replacement that supersedes several older part numbers, including 27-430041, 27-430042, 27-430043, 27-430045, and 27-430047.

Should I use a gasket sealant during installation?

Generally, these types of gaskets are designed to be installed dry on clean, flat surfaces. However, always refer to your specific engine's service manual for the manufacturer's recommendation on using sealants.

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

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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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