MerCruiser 305 CID (5.0L) Service Manual page 266

SERVICE MANUAL NUMBER 24
Voltage Drop In Starting System
This test should be done anytime a voltage drop is suspected.
1. With a fully charged battery, connect volmeter positive (+) lead to the battery positive
(+) post.
2. Connect the voltmeter negative (–) lead to the starter solenoid terminal where the posi-
tive (+) battery cable connects.
NOTE: Connect voltmeter leads to the battery post, NOT the battery cable end.
IMPORTANT: Remove one voltmeter lead before you stop cranking the starter motor
in the following steps to prevent the possibility of voltmeter damage.
3. Crank the engine over and record voltmeter reading. The reading should not exceed .5
volts. A reading over .5 volts suggests excessive resistance.
4. Test the negative (–) battery cable by connecting the voltmeter negative (–) lead to the
battery negative (–) post.
5. Connect the voltmeter positive (+) lead to the starter motor case. Ensure that there is
good contact with metal.
6. Repeat step 3.
7. If either reading was above .5 volts, start with the battery cable and work your way to
the starter checking each connection for resistance.
NOTE: Always ensure that paint or corrosion is not causing the high resistance. The mount-
ing surface under the starter motor and the mounting bolts should be free from paint and
corrosion.
Index
90-861327--1 OCTOBER 1999
STARTING SYSTEM
Page 4A-11