Listed gear-ratio data for 1999 Mariner 40 HP outboards. Match your exact model and lower unit; some models may have more than one gearcase configuration.
1999 Mariner 40 HP
Listed ratio values: 2.00:1
| Model | Gear ratio |
|---|---|
| 40 TwoStroke - 644 cc | 2.00:1 |
| F40 FourStroke - pre-EFI/early generation | 2.00:1 |
Use the ratio that matches your exact outboard model and lower unit, then enter it in the PropSlip calculator.