Generac Power Systems 13 kW NG, 10 kW LP, 7 kW NG Setting Ignition Magneto Armature Air Gap

DC control

Part 4

Section 4.4

Diagnostic tests

Procedure, Adjusting Magneto Flywheel Gap:

Note: The air gap between the ignition magneto and the flywheel on single cylinder engines is not adjustable. Proceed directly to Step 10 for single cylinder engines. For V-twin engines, proceed as follows.

1.See Figure 34. Rotate the flywheel until the magnet is under the module (armature) laminations.

2.Place a 0.008-0.012 inch (0.20-0.30mm) thickness gauge between the flywheel magnet and the module laminations.

Note: A business card is approximately 0.010 inch thick.

3.Loosen the mounting screws and let the magnet pull the magneto down against the thickness gauge.

4.Tighten both mounting screws.

5.To remove the thickness gauge, rotate the flywheel.

6.Repeat the above procedure for the second magneto.

0.008-0.012" GAUGE

MAGNETO

Figure 34. Setting Ignition Magneto (Armature)

Air Gap

7.Repeat Test 70 and check for spark across the spark tester gap

a.A spark test may be conducted with unit dis- sembled by following this procedure.

b.Battery must be connected.

c.J2 Connector must be connected to the printed circuit board.

d.Remove Wire 56 from the SCR located beneath the printed circuit board.

Warning: Make sure all debris is cleared from the engine compartment and all body parts are clear from flywheel before proceeding.

e.Refer to Test 70 to check for spark.

f.Utilizing a jumper wire, connect a wire to the 15B terminal block. Connect the other end to

where Wire 56 was disconnected in Step 7. The engine should crank once the jumper from 15B is connected.

8. If spark was not indicated, replace magnetos.

Note: If gap is only adjusted, ensure to properly test the magnetos by cranking the engine over before reassembly occurs. Spark should be present on both cylinders before reassembly should be completed.

9.If air gap was not out of adjustment, test ground wires.

10.Set a VOM to the measure resistance.

11.Disconnect the engine wire harness from the ignition magnetos (Figure 35).

a.On V-twin generators, remove Wire 18 from the stud located above the oil cooler. See Figure 45.

b.On single cylinder generators, disconnect Wire 18 at the bullet connector. See Figure 44.

ENGINE
WIRE	STUD CONNECTOR
HARNESS
SPARk PLUG
	WIRE 18 TO
	CIRCUIT BOARD

REMOVE LEADS SPARk PLUG

Figure 35. Engine Ground Harness

12.Connect one meter test lead to one of the wires removed from the ignition magneto(s). Connect the other test lead to frame ground. INFINITY should be measured. If CONTINUITY is measured, replace the shutdown harness.

13.Now check the flywheel magnet by holding a screwdriver at the extreme end of its handle and with its point down. When the tip of the screwdriver is moved to within 3/4 inch (19mm) of the magnet, the blade should be pulled in against the magnet.

14.For rough running or hard starting engines check the fly- wheel key. The flywheel's taper is locked on the crankshaft taper by the torque of the flywheel nut. A keyway is provided for alignment only and theoretically carries no load.

Note: If the flywheel key becomes sheared or even partially sheared, ignition timing can change. Incorrect timing can result in hard start- ing or failure to start.

15.As stated earlier, the armature air gap is fixed for single cylinder engine models and is not adjustable. Visually inspect the armature air gap and hold down bolts.

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