CAPACITOR TEST
The capacitor should charge when you use an ohmmeter on the high ohms scale with the proper polarity. The resistance will increase until it goes to (nearly) infinity. If the capacitor is shorted, then it will never charge. If it is open, the resistance will be infinite immediately and won't change. If the polarity of the probes is reversed, it will not charge properly either. Determine the polarity of your meter and mark it. Black is usually negative with VOMs, for example. Confirm with a marked diode. A low reading across a good diode indicates that the positive lead is on the anode (triangle) and negative lead is on the cathode (bar).
CHARGING SYSTEM TESTS
12 V Charging Circuit
To test the operation of the regulator in the EMM, you must be able to run the outboard continuously at approximately 5000 RPM, such as in a test tank or on a marine dynamometer.
The test consists of monitoring the system’s response to a partially discharged battery. Use a variable load tester to discharge the battery.
The regulator requires battery voltage on the red wire to operate. Before proceeding, make sure battery voltage is at the connector red wire when key is ON.
Test Procedure
Disconnect the battery cables at the battery.
Use an inductive amp meter or connect a 0 to 50 A ammeter in series between the red wire(s) of engine wire harness (alternator output from EMM) and the positive (B+) battery cable terminal of starter solenoid.
This outboard has dual output charging. Each output is isolated and regulated. Each output is 25 A. Combined output is approximately 50 A. Refer to engine wiring diagram.
Fluke1 model 334 or 336, Snap-On1 model MT110 or EETA501, and various other amp meters should be available through local tool suppliers.
Reconnect the outboard’s battery cables.
Following the manufacturer’s directions, connect the variable load tester (carbon pile) across the battery terminals. Stevens model LB-85 and Snap-On model MT540D are examples of testers available.
Excessive battery discharge rates might overheat battery causing electrolyte gassing. This might create an explosive atmosphere.
Always work in a well ventilated area.
Variable Load Test Diagram
- Red wire (alternator output from EMM)
- Starter solenoid
- Battery cable terminal (B+)
- Variable load tester
- Ammeter
Battery Charging Graph
Start the outboard and run it at approximately 5000 RPM. Use the variable load tester to draw the battery down at a rate equivalent to the stator’s full output.
- The ammeter should indicate nearly full output, Approximately 50 A (or 25 A for each output) @ 5000 RPM.
Decrease the battery load toward 0 A.
- Ammeter should show a reduced output. As the current draw decreases, the battery voltage should stabilize at approximately 14.5 V.
- If results vary, check stator BEFORE replacing the EMM. See STATOR TESTS on p. 141.
55 V Alternator Circuit
STEP 1
Check battery ground cable for continuity.
STEP 2
With the key switch ON, check battery voltage at battery (12 V), then check voltage on white/red wires at J2 connector of EMM. Use Electrical Test Probe Kit, P/N 342677 and a multimeter set to read 55 VDC. Voltage at EMM connector should be approximately 30 V.
- J2 connector of EMM
STEP 3
With outboard running at 1000 RPM, voltage on white/red wires should increase to 55 V.
Voltage readings at a specific speed (RPM) should be steady.
If there is any other reading, perform Stator Resistance Tests on p. 141 and Stator Voltage Output Test on p. 141. Inspect the stator wiring and connections. Inspect the capacitor wiring, connections, and capacitor. Repair the wiring or replace a faulty capacitor, stator, or EMM.
Auxiliary Battery – Charge Wire
The auxiliary battery charge feature requires auxiliary battery charge kit, P/N 5006253 (or equivalent).
Disconnect all accessories from the auxiliary battery. Auxiliary battery must read a minimum of 8.5 V at the beginning of these tests and remain connected to the outboard during the tests.
STEP 1
Check battery ground cable for continuity.
STEP 2
With the key switch OFF, check battery voltage at auxiliary battery, then check voltage at auxiliary battery connection. If the readings are not the same, replace wire to auxiliary battery. The auxiliary battery wire must be at least 10-gauge and it must be protected by a 50 A fuse or circuit breaker at the battery.
STEP 3
With outboard running at 1000 RPM, voltage must read higher than in STEP 2 and increase steadily to approximately 14.5 V as the outboard RPM increases.
If there is no increase, turn the key switch to OFF and test red/black wire between the EMM and auxiliary battery connection.
- Continuity indicates faulty output from EMM.
Check 12 V alternator output before replacing EMM for faulty auxiliary battery, charge isolator circuit. - No continuity indicates faulty wiring.
