MerCruiser Alpha One Gen II Bellows Kit – 4-Piece Set for 1991 and Newer Models
MerCruiser Alpha One Gen II Bellows Kit – 4-Piece Set for 1991 and Newer Models is backordered and will ship as soon as it is back in stock.
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MerCruiser Alpha One Gen II Bellows Kit – 4-Piece Set for 1991 and ...
MerCruiser Alpha One Gen II Bellows Kit – 4-Piece Set for 1991 and Newer Models is backordered and will ship as soon as it is back in stock.
Product Details
This aftermarket MerCruiser Alpha One Gen II bellows kit combines the three primary bellows used at the sterndrive connection with a bell housing gasket kit. It is intended for Alpha One Generation II applications from 1991 and newer, subject to verification of the drive model and serial number.
The kit includes a shift cable bellows, U-joint bellows, exhaust bellows, and bell housing gasket kit. These components help protect the drive connection from water intrusion and support proper sealing during sterndrive service.
- Four-piece maintenance kit for compatible MerCruiser Alpha One Gen II applications.
- Includes shift cable, U-joint, and exhaust bellows plus a bell housing gasket kit.
- Aftermarket replacement components for sterndrive bellows service.
- Verify the drive model, application, and serial number before ordering.
Part Number References
The following manufacturer and aftermarket references are associated with the kit components. Individual reference numbers identify components, not the complete kit as a single original-equipment part number.
| Kit Component | Reference Numbers | Application Description |
|---|---|---|
| Shift Cable Bellows | Mercury Marine 74639Q02; 74639, 74639A2, 31659; Sierra 18-2753-2 | Shift cable bellows for compatible sterndrive assemblies. |
| U-Joint Bellows | Mercury Marine 816431A1; Sierra 18-2747 | U-joint or drive bellows for Alpha One Gen II applications. |
| Exhaust Bellows | Mercury Marine 18654A1; 32734, 32734A3; Sierra 18-2750 | Exhaust bellows used on compatible No. 1, Gen II, TRS, and Bravo applications. |
| Bell Housing Gasket Kit | Mercury Marine 27-94996Q2; 27-94996, 27-94996A1, 27-94996A2, 27-94996A3, 27-94996A20, 27-94996T2, 27-64818A2, 27-64818A3 | Drive shaft housing-to-bell housing and related bell housing sealing components. |
Compatibility
The primary listed application is MerCruiser Alpha One Gen II, 1991 and newer. Component catalogs also associate the referenced bellows with broader sterndrive families, but component-level references should not be treated as confirmation that every related model accepts this complete four-piece kit.
| Brand | Drive Family | Years | Relevant References | Fitment Notes |
|---|---|---|---|---|
| MerCruiser | Alpha One Gen II | 1991 and newer | 816431A1, 74639Q02, 18654A1, 27-94996Q2 | Primary application. Confirm the drive serial number and bell housing configuration. |
| MerCruiser | R, MR, and earlier Alpha I applications | Selected older applications | Component references may include 816431A1, 18654A1, and 27-94996Q2 | Do not assume complete-kit compatibility solely from a matching component number; verify the exact drive and serial range. |
Important: The reference data identifies the kit's component applications. It does not confirm fitment for every engine horsepower, engine displacement, or sterndrive serial range. Match the original bellows, bell housing, and drive configuration before purchase.
Technical Specifications
- Product Type
- Aftermarket bellows and bell housing gasket kit
- Kit Configuration
- Four-piece set
- Included Bellows
- One shift cable bellows, one U-joint bellows, and one exhaust bellows
- Included Sealing Component
- One bell housing gasket kit
- Primary Drive Application
- MerCruiser Alpha One Gen II, 1991 and newer
- Material
- Marine-service rubber bellows and replacement sealing materials
- Installation
- Replacement installation; professional marine service is recommended
What's in the Box
- 1 x Shift cable bellows assembly
- 1 x U-joint bellows assembly
- 1 x Exhaust bellows assembly
- 1 x Bell housing gasket kit
Clamps, clips, sleeves, straps, sealants, and other installation hardware are not listed as separate kit contents unless supplied with the specific component package. Confirm the package contents against the product photos and order documentation before installation.
Installation Notes
- Turn off the engine, disconnect the battery, and follow the applicable MerCruiser service procedure.
- Raise or remove the sterndrive as required for safe access to the bellows and bell housing.
- Inspect the existing bellows, clamps, mating surfaces, gimbal area, and bell housing for corrosion or damage.
- Remove the old components and clean all mating surfaces thoroughly. Remove old sealant and debris without damaging the sealing surfaces.
- Compare each replacement bellows with the removed part and confirm its orientation before fitting.
- Install the gasket components and bellows using the correct service procedure, approved sealants where specified, and properly positioned clamps.
- Check that the U-joint, exhaust, and shift cable bellows are fully seated and that the sterndrive moves freely without twisting or pulling the bellows.
- Inspect the completed installation for leaks and correct movement before returning the vessel to service.
Maintenance and Inspection
Inspect sterndrive bellows regularly, especially before launching after storage. Replace any bellows showing cracks, hardening, swelling, cuts, loose seating, or water leakage. Because the components operate in the same marine environment, replacing related bellows during the same service interval can help avoid repeated disassembly.
Frequently Asked Questions
What drive does this kit fit?
The primary listed application is the MerCruiser Alpha One Gen II drive from 1991 and newer. Always compare the original parts and verify the drive serial number before ordering.
Does this kit fit every MerCruiser engine?
No. Bellows fitment is determined by the sterndrive and bell housing configuration, not only by engine horsepower or displacement. Matching an engine model alone is not sufficient confirmation.
What component does 816431A1 identify?
816431A1 is associated with the U-joint or drive bellows used on Alpha One Gen II applications. In this listing it refers to the U-joint bellows component, not the complete four-piece kit.
What component does 74639Q02 identify?
74639Q02 is associated with the shift cable bellows component. Related catalog references include 74639, 74639A2, 31659, and Sierra 18-2753-2.
What component does 18654A1 identify?
18654A1 is associated with the exhaust bellows component. Related references include 32734 and 32734A3.
Is this an OEM kit?
No. This listing is for aftermarket replacement components. The manufacturer names and part numbers are provided only to identify application and cross-reference the components.
Should a professional install the kit?
Professional marine service is recommended. Incorrect bellows or gasket installation can allow water intrusion and may cause serious sterndrive damage.
Safety and Fitment Information
- Verify the sterndrive model, bell housing configuration, original component shape, and serial number before ordering.
- Do not rely on horsepower, engine displacement, or a single matching part number as the only fitment check.
- Use the appropriate service manual and installation procedures for the specific MerCruiser drive.
- This is an aftermarket replacement kit and is not manufactured by Mercury Marine.
About Sea Sierra
- Marine Replacement Parts — Components selected for common service and repair applications.
- Application-Focused Listings — Product references are organized to help match replacement components to the original installation.
- Service Support — Verify your drive and serial information before ordering to help ensure the correct replacement.
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