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Page 18 - Index - Page 20
Four Cylinder Engines
1970-1971
337-4406/337-4411 Ignitions
  • WARNING: Check the battery voltage at approximately 3500 RPM, MAXIMUM allowable reading is 16 volts and minimum is 12V. Running below 12V or over 16 volts will damage the ignition. Check for loose connections or a bad battery. Maintenance free batteries are NOT recommended for this application.


  • NOTE: Due to commonly found problems associated with this system, it is recommended that the system be converted over to a 332-2986/393-3736 type. (We offer a conversion kit. Call us for details.)
General:
  1. Clean all battery connections and engine grounds.
  2. Disconnect the mercury tilt switch and retest. If the ignition works properly, replace the mercury switch.
  3. Connect a spark gap tester to the spark plug wires and check for fire on all cylinders. If some cylinders fire and not others, the problem is likely in the distributor cap, rotor button or spark plug wires.
  4. Perform a voltage drop test after the engine is repaired to see if there is a problem with the voltage going to the CD module. At cranking and while the engine is running, use a DC voltmeter and put the black meter lead on the battery POS (+) post and the red meter lead on the positive battery cable at the starter solenoid. Keep the black lead on the battery post and shift the red meter lead to the positive post of the rectifier, then to the red and white terminals on the switch box. If you find a reading above 0.6V, there is a problem at the point where the voltage jumped up. For instance, if the meter reads 0.4V until you get to the white terminal and then jumps to 2.3V on the white terminal –this indicates a problem in the keyswitch, or harness. Repeat the test for the negative battery post by putting the black meter lead on the battery NEG (-) post and the red meter lead on the negative battery cable terminal, then shifting to the engine block, rectifier base and case ground of the CD module.
No fire at all:
  1. Connect a spark gap tester to the high-tension lead coming from the ignition coil and set it to approximately 7/16". When you crank the engine over, if it fires while the spark gap tester is connected to the coil and does not fire through the spark plug wires - there is a problem in the distributor cap, rotor button or spark plug wires.
  2. Check the DC voltage present on the white trigger wire and the red terminal of the switch box while cranking. It MUST be at least 9½ volts. If not, there is a problem in the harness, key switch, starter , battery cables or battery.
  3. Check DVA voltage between the blue terminal and engine ground while cranking (The trigger wire must be connected to the switch box). You should read at least 9V.
  4. Disconnect the wire from the blue terminal of the switch box and connect a jumper wire to the terminal. Strike the other end of the jumper wire against engine ground. The CD module should fire each time. Failure to fire usually indicates a bad CD module.
  5. Check DVA voltage on the green wire going to the coil, it should be over 100 volts at cranking.
No fire or intermittent on one cylinder:
  1. Connect a spark gap tester to the spark plug wires coming from the distributor cap and set the air gap to approximately 7/16".
  2. Align the rotor with #1 spark plug wire. Disconnect the wire from the blue terminal of the switch box and connect a jumper wire to the terminal. Strike the other end of the jumper wire against engine ground. Only the #1 spark plug wire should fire. If another spark plug wire fires, there is a problem in the distributor cap.
  3. Repeat the test for the other cylinders.
Page 18 - Index - Page 20