Intake Manifold Gasket – Fits Mercury/Mariner 30-40 HP (Replaces 27-821370)

$10.94 $17.00

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Intake Manifold Gasket – Fits Mercury/Mariner 30-40 HP (Replaces 27-821370) is backordered and will ship as soon as it is back in stock.

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Product Details

This Intake Manifold Gasket is designed for Mercury/Mariner 30-40 HP, 2-Stroke outboard models with serial numbers from 0G055314 through 1B000001 and up. It ensures a proper seal between the intake manifold and the cylinder block for optimal engine performance.

This part serves as a direct replacement for Mercury part numbers 27-821370 and 821370.

Installation Method: Direct replacement
Fuel Compatibility: Gasoline
Contents: Includes one gasket

Part Number Matrix

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

Brand	Part Number
Mercury	27-821370
Mercury	821370

Engine & Model Compatibility

Confirm your engine model/year in the table below.

For Mercury/Mariner engines, this part is compatible with specific 30 and 40 HP 2-Cylinder models. Please check your serial number against the ranges provided.

Brand	Model	Rated HP	Stroke	Years	OEM Part No.
Mercury/Mariner	30 (2 CYL.)	30	2-Stroke	9854537-0P016999	27-821370
Mercury/Mariner	30 (2 CYL.)	30	2-Stroke	0G055314-0G760299	27-821370
Mercury/Mariner	30 (2 CYL.)	30	2-Stroke	0G760300-0T979999	27-821370
Mercury/Mariner	30 (2 CYL.)	30	2-Stroke	0P017000-0P325499	27-821370
Mercury/Mariner	30 (2 CYL.)	30	2-Stroke	0P325500 & Up	27-821370
Mercury/Mariner	30 (2 CYL.)	30	2-Stroke	0T980000-0T999999	27-821370
Mercury/Mariner	30 (2 CYL.)	30	2-Stroke	1B000001 & Up	27-821370
Mercury/Mariner	40 (2 CYL.)	40	2-Stroke	9854537-0P016999	27-821370
Mercury/Mariner	40 (2 CYL.)	40	2-Stroke	0G055314-0G760299	27-821370
Mercury/Mariner	40 (2 CYL.)	40	2-Stroke	0G760300-0T979999	27-821370
Mercury/Mariner	40 (2 CYL.)	40	2-Stroke	0P017000-0P325499	27-821370
Mercury/Mariner	40 (2 CYL.)	40	2-Stroke	0P325500 & Up	27-821370
Mercury/Mariner	40 (2 CYL.)	40	2-Stroke	0T980000-0T999999	27-821370
Mercury/Mariner	40 (2 CYL.)	40	2-Stroke	1B000001 & Up	27-821370

Technical Specs

Product Type: Intake Manifold Gasket
Installation: Direct replacement
Fuel Type: Gasoline
Dimensions: Length: 21.0 in (533.4 mm), Width: 13.5 in (342.9 mm), Height: 0.4 in (10.16 mm)
Weight: 0.06 lb (0.027 kg)
Other Attributes: Genuine OEM Mercury Marine factory part

What’s in the Box

1 x Gasket (27-821370)

Installation Notes

Disconnect the battery and relieve any pressure in the fuel system.
Remove components obstructing access to the intake manifold, such as the airbox or carburetor.
Carefully unbolt and remove the intake manifold from the cylinder head.
Thoroughly clean all old gasket material and residue from both mating surfaces. Ensure they are clean, flat, and dry.
Position the new gasket correctly; do not use sealant unless specifically required by your engine's service manual.
Reinstall the intake manifold. Tighten bolts in the sequence and to the torque specifications recommended by the manufacturer.
Reassemble all previously removed components.
Reconnect the battery and start the engine, checking carefully for any fuel or vacuum leaks.

Troubleshooting & FAQ

How do I know if this gasket will fit my engine?

This gasket fits a wide range of Mercury/Mariner 30 HP and 40 HP 2-stroke engines. To guarantee fitment, please verify your engine's serial number is included in the ranges shown in the "Engine & Model Compatibility" table.

What are the signs of a failing intake manifold gasket?

Common symptoms include a rough idle, engine misfires, decreased power, poor fuel economy, overheating, or visible coolant/oil leaks from the intake manifold area.

Can I reuse my old gasket?

No. Gaskets are single-use components designed to crush and create a seal. Always install a new gasket whenever the intake manifold is removed to prevent performance-robbing vacuum leaks or fluid leaks.

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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