Listed gear-ratio data for 2004 Mercury 40 HP 2-Stroke outboards. Match your exact model and lower unit; some models may have more than one gearcase configuration.
2004 Mercury 40 HP 2-Stroke
Listed ratio values: 1.83:1
| Model | Gear ratio |
|---|---|
| 2004-2005 | 1.83:1 |
Use the ratio that matches your exact outboard model and lower unit, then enter it in the PropSlip calculator.