Starter Motor Removal - Mercury 25 EFI Service Manual

Test
Number
Use an ohmmeter (R x 1 scale) and connect meter leads between
Test 1
negative (‑) battery post and common powerhead ground.
1. Change the meter to read voltage.
2. Disconnect the black ground wire from test point 2.
Test 2 3. Connect a voltmeter between common engine ground and black
ground wire.
4. Turn the ignition key to "START" or push in the "START" button.
1. Reconnect the black ground wire at test point 2.
2. Connect voltmeter between common engine ground and test
Test 3
point 3.
3. Turn the ignition key to "START" or push in the "START" button.
1. Connect a voltmeter between common engine ground and test
point 4.
Test 4
2. Set the shift control to neutral.
3. Turn the ignition key to "START" or push in the "START" button.
1. Connect a voltmeter between common engine ground and test
point 5.
Test 5
2. Turn the ignition key to "START" or push in the "START" button.
1. Connect a voltmeter between common engine ground and test
point 6.
Test 6
2. Turn the ignition key to "START" or push in the "START" button.
1. Connect a voltmeter between common engine ground and test
point 1.
Test 7
2. Turn the ignition key to "START" or push in the "START" button.
1. Reconnect the black starter motor cable to the starter solenoid.
2. Connect a voltmeter between common engine ground and test
Test 8
point 7.
3. Turn the ignition key to "START" or push in the "START" button.

Starter Motor Removal

Starter Removal
1. Remove the wire harness. Refer to Engine Wire Harness for the removal of the engine wire harness.
2. Remove the support bracket and the IAC filter.
3. Remove the engine oil filter.
4. Remove the high pressure fuel hose clamp at the VST and remove the fuel hose.
5. Remove the air vent assembly hose from the VST.
90-8M0105568 eng MARCH 2016
Starter Does Not Work
Procedure
© 2016 Mercury Marine
Charging and Starting System
Test Result
Continuity Indicated: Proceed to Test 2
No continuity indicated: There is an open
circuit in the black negative (‑) battery cable
between the negative (‑) battery post and the
powerhead.
• Check cable for loose or corroded
connections
• Check cable for open
Reading battery voltage: Check the black
ground wire for poor connection or open
circuit. Reconnect ground wire. Proceed to
Test 7.
No voltage reading: Proceed to Test 3.
Reading battery voltage: Defective starter
solenoid.
No voltage reading: Proceed to Test 4.
Reading battery voltage: The neutral start
switch is open, or a wire is open between
test points 4 and 3.
No voltage reading: Proceed to Test 5.
Reading battery voltage: Defective ignition
switch or start button.
No voltage reading: Proceed to Test 6.
Reading battery voltage:
• Check the fuse in the red wire between
test points 5 and 6.
• Check for a open red wire between test
points 5 and 6.
No voltage reading: Check the black wire
between battery (+) positive terminal and test
point 6.
Reading battery voltage: Listen for the
solenoid click. Proceed to Test 8.
No voltage reading: Defective starter
solenoid.
Reading battery voltage: Check the starter
for a corroded ground to the block. If OK,
check the starter motor.
No voltage reading: Check the starter black
cable for poor connection or open circuit.
Check for a bad ground or a defective starter
relay.
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