Mercury Mariner 8/9.9HP 4-Stroke Factory Service Manual, Page 65Get this manual
TEST 2 No voltage reading; proceed to TEST 3aDisconnect BLACK ground wire(s) from Test Point 2bConnect voltmeter between common engine ground and Test Point 2cTurn ignition key to "Start" position
Battery Voltage
aReconnect BLACK ground wire(s)bConnect voltmeter between common engine ground and Test Point 3cTurn ignition key to "Start" position
12 Volt Reading
Check BLACK ground wire for poor connection or open circuitReconnect ground wire to starter solenoid; proceed to TEST 7
No voltage reading; proceed to TEST 4
12 Volt Reading
Defective starter solenoid
Electric Start Tiller Handle Model
Neutral start switch is open or BLACK leads are disconnected or damaged
No voltage reading; proceed to TEST 5aConnect voltmeter between common engine ground and Test Point 4bTurn ignition key to "Start" position
12 Volt Reading
Neutral start switch is open, or YELLOWRED or BLACK wire is open between Test Points and 3
No voltage reading; proceed to TEST 6Connect voltmeter between common engine ground and Test Point 5