Shift Shaft Bushing Tool – Fits Mercury Mariner 115-200HP (Replaces 91-31107T, 18-9817)

Product Details

The Shift Shaft Bushing Tool is a precision installation tool designed for Mercury Mariner outboard engines ranging from 115 to 200 horsepower. Constructed from high-strength forged steel that has been hardened and zinc-nickel alloy plated, this tool ensures reliable performance during shift shaft bushing installation and removal procedures.

This aftermarket replacement directly replaces Sierra 18-9817, GLM 90140, and Mercury part numbers 91-31107T, 91-31107, 91-23033T, 91-23033, and 91-24150.

• Forged and hardened steel construction ensures greater strength and toughness during installation
• Zinc-nickel plating provides superior corrosion resistance and withstands high-temperature environments
• Meets or exceeds OEM quality standards for reliable, repeatable use

Part Number Matrix

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

Engine & Model Compatibility

Confirm your engine model/year in the table below.

Technical Specs

Material

High Strength Forged Steel, Hardened

Finish

Zinc-Nickel Alloy Plated

Quality Standard

Meets or Exceeds OEM

Corrosion Resistance

High-temperature tolerant with excellent adhesion

Application

Shift Shaft Bushing Installation & Removal

What's in the Box

• 1 × Shift Shaft Bushing Tool

Installation Notes

1. Ensure the outboard engine is completely shut down and the ignition key is removed before beginning work.
2. Remove the lower unit assembly according to your engine's service manual to access the shift shaft area.
3. Use the shift shaft bushing tool to carefully press out the old bushing without damaging the surrounding housing.
4. Inspect the shift shaft bore for debris, corrosion, or damage; clean thoroughly before proceeding.
5. Align the new bushing with the tool and press it evenly into position until fully seated.
6. Verify the bushing is flush and properly aligned before reassembling the lower unit.
7. Reinstall the lower unit, torque all fasteners to specification, and test shift operation before returning to service.

Troubleshooting & FAQ

Which Mercury engines does this tool fit?

This shift shaft bushing tool is designed for Mercury Mariner outboard engines from 115 to 200 horsepower. Always verify your engine's part number against the replacements listed to ensure compatibility.

Can I install the bushing without this tool?

While some technicians attempt installation using makeshift tools, this dedicated tool ensures even pressure distribution and proper alignment, reducing the risk of damage to the bushing or housing.

What are signs that my shift shaft bushing needs replacement?

Common symptoms include excessive play in the shift lever, difficulty shifting gears, grinding noises during gear engagement, or visible wear and scoring on the shift shaft. If you observe any of these, inspect and replace the bushing as needed.

Is this tool reusable?

Yes, the hardened forged steel construction is designed for repeated professional use. Proper care and storage will extend tool life significantly.

How does the zinc-nickel plating benefit this tool?

Zinc-nickel alloy plating offers superior corrosion resistance compared to standard zinc, withstands higher operating temperatures, and provides excellent adhesion, making it ideal for marine environments.

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 against 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.