Powerhead Gasket – Fits Mercury/Mariner 65-125 HP Outboard (Replaces 27-430075)

$14.50

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Product Details

This Powerhead Gasket – Fits Mercury/Mariner 65-125 HP Outboard (Replaces 27-430075) is designed for a precise fit on Mercury and Mariner 65–125 HP 2-Stroke 3 & 4 cylinder outboards, including DFI models, manufactured from 1993 to the present. It serves as the critical seal between the powerhead and the exhaust housing, preventing exhaust leaks and ensuring proper engine compression.

This part is a direct replacement for Mercury part numbers 27-430075, 27-430073, and 27-43007. It also serves as a cross-reference for GLM 32830 and Mallory 9-60043.

Installs between the powerhead and exhaust housing.
Engineered from high-quality composite gasket material to withstand the marine environment.
Includes one gasket as pictured.

Part Number Matrix

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

Brand	Part Number	Notes
Mercury	27-430075	Current part number. Supersedes 27-43007, 27-430073.
Mercury	27-430073	Superseded by 27-430075
Mercury	27-43007	Superseded by 27-430073
GLM	32830	Aftermarket Interchange
Mallory	9-60043	Aftermarket Interchange

Engine & Model Compatibility

Confirm your engine model/year in the table below.

This powerhead gasket is compatible with a wide range of Mercury and Mariner 3- and 4-cylinder outboards. Please verify your specific model and year against the list to ensure correct fitment.

Brand	Model	Rated HP	Stroke	Years	OEM Part No.	Notes
Mercury	65 JET	65	2-Stroke	1993–2006	27-430075	Previously 27-43007, 27-430073
Mercury	65 JET (3 CYL.)	65	2-Stroke	2006–present	27-430075
Mercury	75 (3 CYL.)	75	2-Stroke	1993–present	27-430075
Mercury	75 DFI (3 CYL.)(1.5L)	75	2-Stroke	2006–present	27-430075
Mercury	80 JET	80	2-Stroke	1993–2006	27-430075
Mercury	80 Jet (3 CYL.)(1.5L)	80	2-Stroke	2006–present	27-430075
Mercury	90 (3 CYL.)	90	2-Stroke	1993–present	27-430075
Mercury	90 DFI (3 CYL.)(1.5L)	90	2-Stroke	2000–present	27-430075
Mercury	100 (4 CYL.)	100	2-Stroke	1993–1999	27-430075
Mercury	115 (4 CYL.)	115	2-Stroke	1993–present	27-430075
Mercury	115 DFI (3 CYL.)(1.5L)	115	2-Stroke	2000–present	27-430075
Mercury	115 Pro XS (3 CYL.)(1.5L)	115	2-Stroke	2006–present	27-430075
Mercury	125 (4 CYL.)	125	2-Stroke	1993–present	27-430075
Mercury	125 DFI (3 CYL.)(1.5L)	125	2-Stroke	2006–present	27-430075

Technical Specs

Product Type: Powerhead Base Gasket
Installation: Between powerhead and exhaust housing
Housing Material: Composite/Gasket Material
Dimensions: 28.0" L x 20.0" W x 1.0" H
Warranty: Varies by seller; OEM parts typically 1 year limited warranty

What’s in the Box

1 x Gasket (Replaces 27-430075)

Installation Notes

Ensure the engine is off, cool, and disconnected from the battery and fuel supply.
Remove the engine cowl to access the powerhead.
Systematically loosen and remove the bolts securing the powerhead to the drive shaft housing/exhaust plate. Keep them in order.
Carefully lift the powerhead off the housing. This may require an engine hoist for heavier models.
Remove the old powerhead gasket and discard it.
Thoroughly clean both mating surfaces on the powerhead and the exhaust housing. Remove all old gasket material and corrosion.
Place the new gasket into position, ensuring it aligns with all bolt holes and passages.
Carefully lower the powerhead back onto the housing.
Install and torque the mounting bolts in the sequence and to the values specified in your engine's service manual.
Reconnect fuel lines, electrical connections, and reinstall the cowl.
After reassembly, start the engine and check for any exhaust or water leaks around the gasket.

Troubleshooting & FAQ

How can I be sure this gasket fits my specific outboard model?

The best way to confirm fitment is to check your engine's model, horsepower, and year against our detailed compatibility table. You can also verify by cross-referencing your existing gasket's part number with those listed in the Part Number Matrix.

What are the common signs of a failed powerhead gasket?

Symptoms of a bad powerhead gasket include engine overheating, a noticeable loss of power or compression, water in one or more cylinders (which can cause a misfire), or visible exhaust/water leaking from the seam between the powerhead and the exhaust housing.

Do I need to use gasket sealant or adhesive with this part?

Most modern gaskets, including this one, are designed to be installed dry. The composite material creates a seal when compressed. Always consult your engine’s official service manual, as some specific models may have different requirements.

When should a powerhead gasket be replaced?

A powerhead gasket does not have a regular service interval. It should be replaced anytime the powerhead is removed for service or if it has failed, which would be indicated by symptoms like overheating or compression loss.

Is this an OEM part?

This listing is for a high-quality aftermarket replacement part, not an OEM component. It is engineered to meet or exceed OEM specifications for fit, form, and function, providing a reliable and cost-effective alternative.

What is the difference between Mercury part 27-430075 and 27-430073?

Part number 27-430075 is the latest version that supersedes, or replaces, the older 27-430073. They are functionally identical, and our aftermarket gasket is designed to replace all previous versions.

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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