Listed gear-ratio data for 1999 Mercury 13.5 HP outboards. Match your exact model and lower unit; some models may have more than one gearcase configuration.
1999 Mercury 13.5 HP
Listed ratio values: 2.00:1, 2.42:1
| Model | Gear ratio |
|---|---|
| 0P134638-0P400999 | 2.00:1, 2.42:1 |
| 0P401000-UP | 2.00:1, 2.42:1 |
Use the ratio that matches your exact outboard model and lower unit, then enter it in the PropSlip calculator.