Ignition System Test
- Make sure battery is fully charged and that there is fuel in tank. Remove any spark plug wire and connect test spark plug to wire. Test spark plug must have electrode gap set at 0.16" (4 mm). Make sure spark plug is well grounded.
- If no spark is present, go to step 9). If spark is present, check ignition timing and adjust if necessary. Check fuel system to ensure that engine is receiving sufficient fuel. If not, repair fuel system.
- If fuel system is okay, rotate ignition control unit around ground bolt until fuse is visible from side. Pull cover away from fuse, but DO NOT remove fuse.
- Connect voltmeter between terminals 2 and 4 and turn ignition on. Voltmeter should indicate battery voltage. If reading is incorrect, check wiring between ignition switch and control unit. Repair wiring as required.
- If voltage is correct, turn ignition off and disconnect wiring at ignition coil. Using a ohmmeter, measure primary winding resistance between coil terminals 1 and 15. Reading should be 0.52-0.76 ohms.
- Measure resistance between coil tower and negative terminal 1 to obtain coil secondary winding resistance. Reading should be 2500-3500 ohms. If coil resistance is incorrect, replace ignition coil.
- If coil resistance is correct, reconnect coil terminals and disconnect wires from distributor. Connect a voltmeter between coil terminals 1 and 15 and turn ignition on.
- Voltmeter should drop from about 6 volts to zero volts within 1-2 seconds. If not, replace control unit. If voltage drop is correct, the engine should start. Ignition system is NOT at fault.
- Check distributor rotor, cap, spark plug wires and spark plugs. Ignition coil wire resistance should be 500-1500 ohms. Spark plug wire resistance should be 2000-4000 ohms. Distributor rotor resistance should be 1000 ohms.
- Check for spark across test spark plug (step 1). If spark occurs, rotate ignition control unit around ground bolt until fuse is visible from side. Pull cover away from fuse, but DO NOT remove fuse.
- Connect voltmeter between terminals 2 and 4 and turn ignition on. Voltmeter should indicate battery voltage. If reading is incorrect, check wiring between ignition switch and control unit. Repair wiring as required.
- If voltage is correct, disconnect wiring from distributor. Check voltage at connector's positive and negative terminals. If battery voltage is not present, check wiring between distributor and control unit. If wiring is okay, replace control unit.
- If battery voltage is present, connect voltmeter between terminal 6 and 3 on control unit. DO NOT remove fuse. Remove distributor cap and dust cover. Crank engine until any aperture of trigger wheel is in gap of Hall Effect sending unit.
- Turn ignition on. Voltage should be 0.4 volts or less. If voltage is incorrect, Hall Effect sending unit is defective. Replace distributor. If voltage is correct, crank engine until any trigger wheel blade enters Hall Effect sending unit gap. See Fig 1.
- Voltage should now be 1.0 volts or more. If voltage is incorrect, Hall Effect sending unit is defective. Replace distributor. If voltage is correct, perform steps 5) through 8).