Shift Cover Gasket – Fits Mercury Marine/Mercruiser 135-300HP Engines (Replaces 27-880729)

$3.19 $5.00

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Shift Cover Gasket – Fits Mercury Marine/Mercruiser 135-300HP Engines (Replaces 27-880729) is backordered and will ship as soon as it is back in stock.

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Product Details

This replacement Shift Cover Gasket is designed to fit a wide range of Mercury Marine and Mercruiser outboard engines, specifically various 135HP to 300HP models, including 3.0L DFI/EFI and Verado 4-cylinder and 6-cylinder 4-stroke outboards manufactured from 2004 to the present.

It serves as a direct replacement for Mercury Marine part numbers 27-880729 and 880729, ensuring a precise fit and reliable seal for the gear housing and driveshaft assembly.

Installs as a direct OEM-equivalent replacement.
Engineered for marine gear housing and driveshaft applications.
This is a factory original equipment equivalent part.

Part Number Matrix

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

Brand	Part Number
Mercury Marine	27-880729
Mercury Marine	880729

Engine & Model Compatibility

Confirm your engine model/year in the table below.

This gasket is compatible with a variety of Mercury and Mariner Verado and DFI/EFI models. Please verify your specific engine serial number range if multiple options exist for your model and year.

Mercury/Mariner Verado 4-Cylinder Models

Brand	Model	Rated HP	Stroke	Years	OEM Part No.	Notes
Mercury	Verado	135	4-Stroke	2004–Present	27-880729	Multiple serial number ranges
Mercury	Verado	150	4-Stroke	2004–Present	27-880729	Multiple serial number ranges
Mercury	Verado	175	4-Stroke	2004–Present	27-880729	Multiple serial number ranges
Mercury	Verado	200	4-Stroke	2004–Present	27-880729	4-cylinder version

Mercury/Mariner Verado 6-Cylinder Models

Brand	Model	Rated HP	Stroke	Years	OEM Part No.	Notes
Mercury	Verado	200	4-Stroke	2004–Present	27-880729	6-cylinder version
Mercury	Verado	225	4-Stroke	2004–Present	27-880729
Mercury	Verado	250	4-Stroke	2004–Present	27-880729
Mercury	Verado	275	4-Stroke	2004–Present	27-880729
Mercury	Verado	300	4-Stroke	2004–Present	27-880729
Mercury	Verado Pro	200	4-Stroke	2004–Present	27-880729
Mercury	Verado Pro	250	4-Stroke	2004–Present	27-880729
Mercury	Verado Pro	300	4-Stroke	2004–Present	27-880729
Mercury	Verado Pro	350	4-Stroke	2014–Present	27-880729
Mercury	Verado	350	4-Stroke	2014–Present	27-880729
Mercury	Verado	350SCi	4-Stroke	2006–2014	27-880729
Mercury	Verado	400	4-Stroke	2015–Present	27-880729

Mercury/Mariner 3.0L DFI/EFI Models

Brand	Model	Rated HP	Stroke	Years	OEM Part No.	Notes
Mercury	Optimax/DFI	200	2-Stroke	2004–Present	27-880729	DFI 3.0L
Mercury	DFI	200	2-Stroke	2004–Present	27-880729	DTS versions
Mercury	Pro XS	200	2-Stroke	2004–Present	27-880729	DFI 3.0L
Mercury	DFI	225	2-Stroke	2004–Present	27-880729	3.0L models
Mercury	DFI	225	2-Stroke	2004–Present	27-880729	DTS versions
Mercury	Pro XS	225	2-Stroke	2004–Present	27-880729	3.0L models
Mercury	DFI	250	2-Stroke	2004–Present	27-880729	3.0L models
Mercury	Pro XS	250	2-Stroke	2004–Present	27-880729	3.0L DFI
Mercury	EFI	200	4-Stroke	2004–Present	27-880729	3.0L models
Mercury	EFI	225	4-Stroke	2004–Present	27-880729	3.0L models
Mercury	EFI	250	4-Stroke	2004–Present	27-880729	3.0L models

Technical Specs

Product Type: Shift Cover Gasket
Installation: Direct OEM replacement
Dimensions: 10.0" L x 10.5" W x 0.4" H
Weight: 0.06 lbs (0.027 kg)
Application: Gear housing, driveshaft
OEM Part Number: 27-880729
UPC/GTIN: 745061634060
Other Technical Attributes: Factory original equipment part

What’s in the Box

1 x Shift Cover Gasket (27-880729)

Installation Notes

Ensure the engine is off and the battery is disconnected before starting work.
Place a drain pan under the lower unit and remove the drain/fill screws to empty the gearcase lubricant.
Remove the lower unit (gearcase) from the outboard's midsection according to your service manual.
Locate and unbolt the shift cover. Carefully remove the old cover and gasket, noting component orientation.
Thoroughly clean both mating surfaces on the gearcase and the shift cover, removing all old gasket material and sealant residue.
Position the new gasket on the gearcase surface, ensuring all bolt holes align perfectly.
Reinstall the shift cover and tighten the bolts to the manufacturer's specified torque in the correct sequence.
Reinstall the lower unit, then refill the gearcase with the correct type and amount of marine gear lubricant before returning to service.

Troubleshooting & FAQ

What are the signs of a failing shift cover gasket?

The most common sign is a gear lube leak from the area where the shift shaft enters the gearcase. You may also notice water intrusion into the gear oil, which will make the oil appear milky or creamy. Difficulty shifting can also occur in some cases.

How can I confirm this is the correct gasket for my specific engine?

While this gasket fits a wide range of models, always verify compatibility by checking the compatibility tables on this page against your engine's model, horsepower, and year. For absolute certainty, cross-reference the OEM part number (27-880729) with your engine's service manual or parts diagram.

Is any sealant required during installation?

Generally, new gaskets are designed to be installed on clean, dry surfaces without any additional sealant. However, always consult your engine's specific service manual, as some applications may recommend a light application of a specific sealant.

How often should this gasket be replaced?

There is no fixed replacement interval for this gasket. It should be replaced anytime the shift cover is removed for service, or if you detect a leak or water intrusion from the shift cover area.

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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Shift Cover Gasket – Fits Mercury Marine/Mercruiser 135-300HP Engines (Replaces 27-880729)

Worry-free returns

Delivery and Shipping

Product Details

Part Number Matrix