1985 Mercury Outboard V-300 V-3.4L Shop Service Manual, Page 38Get this manual
I No voltage reading: roceed to TEST 3
Disconnect black ground wire(5) from Test POint 2(Figure 4) bConnect voltmeter between common engine ground and Test Point 20 Turn ignition key to "Slarl" position
Battery Voltage
TEST Reconnect black ground wirebConnect voltmeter between common engine ground and Test Point 3
Check black ground wife for poor connection or open clrcuilReconnect round wire to
Turn ign ition key to "Slarl" position
starler solenoid; proceed to TEST 7
No voltage readingproceed to TE ST 4
12 Volt Reading
Defective sta rter solenoid