Hinge Pin Tool – Fits MerCruiser Alpha & Bravo Sterndrive (Replaces 91-78310, 18-9861)

Hinge Pin Tool – Fits MerCruiser Alpha & Bravo Sterndrive (Replaces 91-78310, 18-9861)

This specialty hinge pin tool is designed for removing and installing the hinge pins on MerCruiser sterndrive bell housings. It is compatible with a wide range of models, including Alpha One (Gen I & II), Bravo (I, II, & III), MC-1, R, and MR sterndrives.

This tool is a direct aftermarket replacement for Mercury part number 91-78310, Sierra 18-9861, GLM 90200, and Mallory 9-79805, ensuring a precise fit for service and maintenance.

• Material: Constructed from hardened steel for durability and strength.
• Function: Allows for proper removal and installation of hinge pins on both port and starboard sides.
• Tool Style: 12-Point Allen style head for secure engagement with the hinge pin bolt.

Part Number Cross-Reference

Use this table to confirm equivalent part numbers across OEM and aftermarket brands.

Compatible Engine Models

Confirm your engine model/year in the table below. For Mercury owners, here’s a guide to help you identify your engine’s serial/model: Mercury Serial Number Guide. You can also review exploded diagrams to verify part numbers: Mercury Parts Diagrams & Catalog.

Technical Specifications

Package Contents

1 x Hinge Pin Tool (Replaces 91-78310, 18-9861, 90200, 9-79805)

Installation Guide

This tool is used to separate the sterndrive housing from the gimbal ring by acting on the hinge pin bolt. Follow these general steps for installation:

1. Access the Hinge Pin: The trim and tilt sender unit typically covers the hinge pin. You must remove this sender first to gain access to the bolt.
2. Engage the Tool: Place the 12-point Allen style head of the tool onto the hinge pin bolt.
3. Remove the Pin: Apply force to unscrew and remove the hinge pin. This process will separate the housing from the gimbal ring.
4. Reinstallation: To reinstall, reverse the process, using the tool to tighten the hinge pin bolt to the manufacturer's specified torque. The tool works for both port and starboard side pins.

Troubleshooting & FAQ

Q: How do I know if this hinge pin tool will fit my sterndrive?
A: This tool is designed for a wide range of MerCruiser sterndrives, including Alpha One (Gen I & II), Bravo (I, II, III), MC-1, R, and MR models. Please consult the "Compatible Engine Models" table to verify your specific model and year. It is a direct replacement for OEM part number 91-78310 and other aftermarket numbers.

Q: What is this tool specifically used for?
A: This is a specialty 12-point Allen style tool designed for the removal and installation of the hinge pins that connect the gimbal housing to the gimbal ring on MerCruiser sterndrives.

Q: Do I need to remove anything before using this tool?
A: Yes, on most compatible models, the trim and tilt sender assembly covers the hinge pin bolt. You will need to remove this sender unit first to access the hinge pin.

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 shipping—typically 5–15 days worldwide—and 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 exist—even if your model is listed—do 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 5–15 days.
• Direct from Manufacturer: Competitive pricing without compromising quality.