Intake/Exhaust Manifold Gasket for MerCruiser 120/140, 2.5L and 3.0L Engines – Replaces Mercury 27-96429
Intake/Exhaust Manifold Gasket for MerCruiser 120/140, 2.5L and 3.0L Engines – Replaces Mercury 27-96429 is backordered and will ship as soon as it is back in stock.
Worry-free returns
Worry-free returns
Shop with confidence. If you’re not completely satisfied, eligible items may be returned within the return window, provided they are unused and in original packaging.
If the return is due to our error or a defective item, we’ll make it right.
Please contact us before returning any item.
Delivery and Shipping
Delivery and Shipping
Orders are typically processed within 1–2 business days.
U.S. orders usually arrive within 6–15 days, depending on stock location and destination.
International delivery times may vary due to customs processing.
Tracking information will be provided once your order ships.
Intake/Exhaust Manifold Gasket for MerCruiser 120/140, 2.5L and 3.0...
Intake/Exhaust Manifold Gasket for MerCruiser 120/140, 2.5L and 3.0L Engines – Replaces Mercury 27-96429 is backordered and will ship as soon as it is back in stock.
Product Details
This replacement intake/exhaust manifold gasket is intended for selected MerCruiser four-cylinder engines using the GM 153 CID 2.5L or GM 181 CID 3.0L engine family. Catalog applications identify the related Mercury Marine reference as 27-96429 and describe the applicable 2.5L and 3.0L engines as 1983–1995 non-LX applications.
The gasket is installed at the manifold-to-cylinder-head sealing joint. It is an aftermarket replacement for the referenced marine engine application; compare the original gasket, manifold design, engine designation and serial-number information before ordering.
- For selected MerCruiser four-cylinder 2.5L and 3.0L applications.
- Designed for the intake/exhaust manifold sealing interface identified by the application catalogs.
- Aftermarket replacement for Mercury Marine reference 27-96429.
- Confirm the engine configuration and non-LX application before installation.
Part Number Matrix
These references are provided for identification and cross-reference purposes. They do not replace application verification.
| Brand or Catalog Reference | Part Number | Reference Type |
|---|---|---|
| Mercury Marine | 27-96429 | OEM reference |
| GLM | 33570 | Catalog cross-reference |
| Sierra | 18-1204-1 | Catalog cross-reference; verify package configuration separately |
Engine & Model Compatibility
The application information below is based on catalog descriptions for the 27-96429 reference. Model, year, engine configuration and serial-number conditions must be checked together. The catalog relationship supports the general application below but does not establish every individual serial-number range.
| Brand | Engine Family or Model | Rated HP | Stroke | Application Years | OEM Reference | Application Notes |
|---|---|---|---|---|---|---|
| MerCruiser | 120 / 2.5L L4, GM 153 CID | 120 | 4-Stroke | 1983–1989 | 27-96429 | Catalog-listed 2.5L four-cylinder application; verify engine and manifold configuration. |
| MerCruiser | 140 / 3.0L L4, GM 181 CID | 140 | 4-Stroke | 1983–1995 | 27-96429 | Catalog-listed 3.0L four-cylinder non-LX application; verify year and serial number. |
| MerCruiser | 3.0L/LX L4 | Not confirmed for this replacement | 4-Stroke | 1990 and later | 27-96429 | Do not assume LX fitment. Confirm the exact manifold and gasket design before ordering. |
Technical Specs
- Product Type
- Intake/exhaust manifold gasket
- Application
- Selected MerCruiser four-cylinder marine gasoline engines
- Engine Families
- GM 153 CID 2.5L and GM 181 CID 3.0L
- Installation Location
- Between the cylinder head and intake/exhaust manifold mating surfaces
- Fuel Type
- Gasoline
- OEM Reference
- Mercury Marine 27-96429
- Application Limitation
- Catalog-listed 1983–1995 non-LX applications; verify the exact engine and serial number
- Part Construction
- Replacement gasket; material, color and dimensional specifications are not provided in the available product records
What’s in the Box
- Manifold gasket replacement for the listed application.
- Package quantity and any additional installation hardware are not confirmed in the available product records; do not assume bolts, sealant or other components are included.
Installation Notes
- Disconnect the vessel's battery and allow the engine to cool completely.
- Drain the engine block and manifold cooling system as required by the service procedure.
- Label and remove components that obstruct access to the manifold, such as fuel lines, wiring or linkages.
- Loosen and remove the manifold mounting bolts in the sequence specified by the engine service manual.
- Remove the manifold and old gasket without damaging the cylinder-head or manifold mating surfaces.
- Clean both mating surfaces thoroughly and check them for corrosion, warping or damage.
- Compare the replacement gasket with the removed gasket and confirm the ports and bolt holes are correctly oriented.
- Position the gasket and reinstall the manifold according to the engine manufacturer's service instructions.
- Hand-tighten the bolts, then tighten them in the specified sequence and to the specified torque values.
- Reinstall all removed components and reconnect the cooling system and battery.
- Run the engine according to the service procedure and inspect the manifold joint for exhaust, water or coolant leakage.
Troubleshooting & FAQ
How can I confirm this gasket fits my specific engine?
Confirm that your engine is a MerCruiser four-cylinder 2.5L or 3.0L model within the catalog-listed application, then compare the engine model, year, serial number, manifold design and old gasket shape. The OEM reference 27-96429 is an identification aid, not a substitute for complete fitment verification.
Is this gasket for both 120 HP and 140 HP engines?
Catalog application data associates this reference with selected 120 HP 2.5L and 140 HP 3.0L four-cylinder MerCruiser applications. Verify the exact year, serial number and manifold configuration before purchase.
Does this gasket fit every MerCruiser 3.0L or 3.0L LX engine?
No. The available catalog information identifies 3.0L non-LX applications and does not confirm universal LX fitment. Check the engine designation, serial number and manifold design before ordering.
Is this an OEM Mercury Marine gasket?
No. This listing is for an aftermarket replacement. Mercury Marine 27-96429 is shown as the OEM reference used for identification and cross-reference.
What are common symptoms of a failed manifold gasket?
Possible symptoms include exhaust or water leakage at the manifold joint, ticking or hissing noise that changes with engine speed, reduced performance, and overheating when a cooling-water leak is present. Diagnose the complete system before replacing the gasket.
Should sealant be used during installation?
Do not apply sealant unless the engine or gasket manufacturer's service instructions specifically require it. Follow the applicable service manual for surface preparation, gasket orientation, tightening sequence and torque.
Is the package a complete manifold repair kit?
No complete repair kit is established by the available records. The listing is for the replacement manifold gasket; bolts, sealant, manifold parts and other hardware are not confirmed as included.
Shipping speed & cost
Shipping availability, delivery estimates and cost are shown at checkout and may vary by destination and service selected.
Warranty & returns
Warranty and return eligibility are governed by the applicable store policy. Review the current policy before ordering and retain the order information if assistance is needed.
Safety & Important Info
- Verify the engine model, year, serial number, manifold design and original gasket before ordering.
- Do not rely on horsepower or displacement alone to confirm fitment.
- This is an aftermarket replacement, not an OEM Mercury Marine component.
- Use the engine service manual for cooling-system draining, gasket installation, bolt sequence and torque specifications.
- Professional installation is recommended when working on marine exhaust and cooling systems.
About Sea Sierra
- Pro-Grade Standards — We supply marine replacement parts selected for practical service applications.
- Global Fulfillment — Delivery options and estimated transit times are displayed at checkout.
- Application-Focused Support — Use the engine model, serial number and original-part details when requesting fitment assistance.
Payment & Security
Payment methods
Your payment information is processed securely. We do not store credit card details nor have access to your credit card information.
