Mercury Mariner 4, 5, and 6HP 4-Stroke Factory Service Manual, Page 73Get this manual

TIMING AND SYNCHRONIZATION
4Multi-MeterDVA Tester (91-99750)

5DMT 2000 Digital TachometerMulti-Meter (91-854009A1)

• ATV
• Jet Ski
• Outboard Motors
• Personal Watercraft
• Snowmobiles
• Stern Drives