2009 Yamaha F40 Outboard Service Manual, Page 119Get this manual

Charging units and componentsIgnition units and components Spark checker (spark gap tester) a: YM-34487 4Remove the special service tool a, and then connect the spark plug capsb
Checking the engine ECM
1Disconnect the ignition coil couplers and then connect the test harness (2 pins) a2Measure the engine ECM output peak voltagea

5Check the wiring harness for continuity

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