Description
Hinge Pin ToolFits Mercury/MerCruiser Sterndrive Alpha 1 Gen 1 & 2, Bravo I II III
This is a specialized service tool designed to remove and install hinge pins in Mercury MerCruiser sterndrive units. It is compatible with a wide range of drives, including Alpha One (Gen 1 and Gen 2) and all Bravo series (I, II, and III).
This tool is a direct replacement for Mercury/MerCruiser part 91-78310 and other aftermarket equivalents.
- Material: Constructed from high-strength machined steel for durability.
- Installation: Designed for manual use with a standard socket wrench.
- Function: Used to remove and install hinge pins from the bell housing.
Part Number Cross-Reference
Use this table to confirm equivalent part numbers across OEM and aftermarket brands.
| Brand | Part Number |
|---|---|
| Mercury/MerCruiser | 91-78310 / 9178310 |
| Sierra | 18-9861 |
| GLM | 90200 |
| Mallory | 9-79805 |
Compatible Engine Models
Confirm your engine model/year in the table below. For Mercury owners, heres a guide to help you identify your engines serial/model: Mercury Serial Number Guide. You can also review exploded diagrams to verify part numbers: Mercury Parts Diagrams & Catalog.
| Brand | Model | Application | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|
| MerCruiser | Alpha One Gen 1 | Sterndrive | All | 91-78310 | Used to remove/install hinge pins |
| MerCruiser | Alpha One Gen 2 | Sterndrive | All | 91-78310 | Used to remove/install hinge pins |
| MerCruiser | Bravo I | Sterndrive | All | 91-78310 | Used to remove/install hinge pins |
| MerCruiser | Bravo II | Sterndrive | All | 91-78310 | Used to remove/install hinge pins |
| MerCruiser | Bravo III | Sterndrive | All | 91-78310 | Used to remove/install hinge pins |
| MerCruiser | Bravo X | Sterndrive | All | 91-78310 | Used to remove/install hinge pins |
| MerCruiser | Bravo XR | Sterndrive | All | 91-78310 | Used to remove/install hinge pins |
| MerCruiser | Bravo XZ | Sterndrive | All | 91-78310 | Used to remove/install hinge pins |
| MerCruiser | MC-1 | Sterndrive | All | 91-78310 | Used to remove/install hinge pins |
| MerCruiser | MR | Sterndrive | All | 91-78310 | Used to remove/install hinge pins |
Technical Specifications
| Specification | Value |
|---|---|
| Product Type | Service Tool (Hinge Pin Tool) |
| Installation | Manual |
| Material | Machined Steel |
| Color | Silver |
| Thread Size | Matches MerCruiser sterndrive hinge pin threading |
| Warranty | 1 Year |
| Other Technical Attributes | 12-point design for use with standard socket wrench |
Package Contents
- 1 x Hinge Pin Tool (Replaces 91-78310)
Installation Guide
- Secure the sterndrive in a stable position, trimming it to provide clear access to the hinge pins.
- Align the Hinge Pin Tool with the head of the hinge pin you intend to remove.
- Attach a standard socket wrench to the 12-point head of the tool.
- Apply firm, steady pressure counter-clockwise to loosen and unthread the hinge pin from the gimbal housing.
- Once the old pin is removed, clean the threads and prepare the new hinge pin for installation.
- Position the new hinge pin and use the tool to thread it into place, turning clockwise.
- Tighten the hinge pin to the manufacturer’s specified torque to ensure a secure fit.
Troubleshooting & FAQ
Q: How do I confirm this tool will fit my sterndrive?
A: This tool is compatible with all Mercury MerCruiser Alpha One (Gen 1 and 2), Bravo (I, II, III, X, XR, XZ), MC-1, and MR sterndrive units. It is specifically designed as a direct replacement for OEM part number 91-78310 and related aftermarket parts.
Q: What makes this tool different from a standard socket?
A: This is a purpose-built tool machined to fit the unique shape of the sterndrive hinge pins perfectly. Using a standard socket or incorrect tool can strip the pin head, making removal extremely difficult.
Q: Do I need any other special tools for the job?
A: While this tool addresses the hinge pin itself, you will need a standard socket wrench to operate it. We also recommend having a torque wrench to ensure the new pin is tightened to the correct OEM specification.
Q: OEM vs. Aftermarket?
A: This listing is an aftermarket replacement part (not an OEM component). We build to OEM specifications using comparable-grade materials. Production is done in an ISO9002-certified facility, and each batch is inspected for consistent performance.
Q: How fast do you ship and how much does it cost?
A: We offer fast global shippingtypically 515 days worldwideand standard shipping is free. Expedited options are available at checkout depending on your location.
Q: What is your warranty and return policy?
A: This product includes a 1-year warranty against manufacturing defects under normal use. If something goes wrong, contact our support team with your order details. Returns are accepted within our standard return window (unused & in original condition); please see our policy page or reach out for instructions.
Important Notes
- Verify that the product images and specifications match your original part. If discrepancies existeven if your model is listeddo not proceed with the purchase.
- This product is an aftermarket replacement part and is not an OEM component.
- Professional installation is recommended to ensure safety and optimal performance.
Why Choose JLM MARINE?
- Quality Assured: As a trusted manufacturer for over 20 years, we supply top marine brands globally.
- Fast Global Shipping: Free delivery worldwide in 515 days.
- Direct from Manufacturer: Competitive pricing without compromising quality.
