Mercury & Mariner 2004-2014 3-Cylinder 2-Stroke 75/90/115 HP Optimax Outboard Gearcase Parts Diagrams

Browse our dedicated page featuring OEM-grade lower unit components for 2004–2014 Mercury & Mariner 75-90-115 HP Optimax 3-cylinder outboards. Whether you're repairing or rebuilding, this catalog offers comprehensive parts diagrams and high-quality parts—including gearcase rebuild kits, bearings, seal kits, propshafts, clutch dogs, shim kits, and more. Perfect for marine technicians, DIY enthusiasts, and boat owners seeking accurate and reliable replacement parts for Optimax engines.

Complete Rebuild Kit

The following parts correspond to the numbers on the diagram above:

1. Inner Forward Gear Bearing
2. Outer Forward Gear Bearing
3. Top Drive Shaft Bearing
4. Bottom Drive Shaft Bearing
5. Reverse Gear Thrust Bearing
6. Forward Carrier Gear Bearing
7. Aft Carrier Bearing
8. Cam Follower Kit
9. Gear Set
• 75-90 HP 1998-2006
• 115 HP Optimax
10. Clutch Dog
11. Clutch Dog Pin
12. Clutch Dog Spring
13. Prop Shaft
14. Bearing Carrier
15. Drive Shaft
16. Pinion Nut
17. Shim Kit

 We also offer the following items:

• Shift Cam
• Water Pump Kit
• Lower Seal Kit
• Bearing Kit