- Joined
- Mar 1, 2000
- RO Number
- 6
- Messages
- 231
TROUBLESHOOTING MERCURY BATTERY CD IGNITIONS
(NOTICE: Maintenance-free batteries are not recommended for use with these systems!)
NOTE: DVA stands for Digital Voltage Adaptor, I.E. Peak Reading Voltmeter
A large portion of the problems with the battery CD units are caused by low battery voltage or bad ground connections. Low Voltage symptoms are weak fire or weak erratic firing of cylinders.
WARNING!: BATTERY REVERSAL WILL USUALLY DESTROY BATTERY CDs AND TRIGGERS.
1) Check all battery and ground connections.
2) Dead or no fire until you let off of the key switch: Check the voltage on the red and white ignition wires at the CD unit. If the voltage is less than 9ВЅ volts during cranking there is a problem in the battery wires or ignition switch circuit. These units require at least 9ВЅ volts to fire properly. On a 332-2986 switch box, check the voltage on the brown terminal (white/black for 332-4796) where the trigger is connected, It requires at least 9V at cranking. DVA check between the white and black wires (black and blue on 332-4796). You should read at least 2 ВЅ V at cranking. Connect a jumper wire directly from the battery pos (+) terminal to the red and white ignition wires (the red wire is not needed for CDI units).
CAUTION: DO NOT CONNECT THE JUMPER WIRE TO THE WHITE TRIGGER TERMINAL. Retest.
ATTENTION: In order to kill the engine if it cranks, the jumper wire has to be disconnected and/or choke the engine. If the engine still fails to crank, recheck voltage as above. If low, replace battery and retry. If there is still no fire, disconnect points wire (or trigger wires) and connect the Battery CD tester, according to the instructions on the back of the tester, and align rotor with a spark plug wire. Connect a spark gap tester to all spark plug wires and turn the ignition switch on. If the CD unit fires to only one spark plug wire, check points wire (for breaks and shorts) or trigger, If ANY other spark plug wire fires besides the one the rotor is aligned with, the distributor cap and rotor should be replaced, The Battery CD tester will fire the system to approximately 3000 RPM. If the Battery CD tester is not used, see related drawing below. If the CD unit fails to fire with this hookup, it is usually bad. Following the instructions included with the Trigger Tester, check the trigger to see if it is good or bad.
3) Engine cranks and fires as long as starter is engaged: This problem usually indicates a bad trigger.
4) Check the ignition coil: An open, cracked or poorly grounded coil can burn out a battery CD.
5) Check the DVA voltage on the primary input wire to the coil using the Fluke meter with the peak reading voltage adapter, or CD 77. The reading should be approximately 100 volts or more for OEM CD's, and 200+ for CDI Electronic units.
6) Inline engines with internal exhaust plate: If engine speeds up when you remove one spark plug wire, the internal exhaust plate is more than likely warped.
7) These tests can be performed on the bench or on the engine.
NOTE: Disconnect the trigger mechanism prior to testing!
(NOTICE: Maintenance-free batteries are not recommended for use with these systems!)
NOTE: DVA stands for Digital Voltage Adaptor, I.E. Peak Reading Voltmeter
A large portion of the problems with the battery CD units are caused by low battery voltage or bad ground connections. Low Voltage symptoms are weak fire or weak erratic firing of cylinders.
WARNING!: BATTERY REVERSAL WILL USUALLY DESTROY BATTERY CDs AND TRIGGERS.
1) Check all battery and ground connections.
2) Dead or no fire until you let off of the key switch: Check the voltage on the red and white ignition wires at the CD unit. If the voltage is less than 9ВЅ volts during cranking there is a problem in the battery wires or ignition switch circuit. These units require at least 9ВЅ volts to fire properly. On a 332-2986 switch box, check the voltage on the brown terminal (white/black for 332-4796) where the trigger is connected, It requires at least 9V at cranking. DVA check between the white and black wires (black and blue on 332-4796). You should read at least 2 ВЅ V at cranking. Connect a jumper wire directly from the battery pos (+) terminal to the red and white ignition wires (the red wire is not needed for CDI units).
CAUTION: DO NOT CONNECT THE JUMPER WIRE TO THE WHITE TRIGGER TERMINAL. Retest.
ATTENTION: In order to kill the engine if it cranks, the jumper wire has to be disconnected and/or choke the engine. If the engine still fails to crank, recheck voltage as above. If low, replace battery and retry. If there is still no fire, disconnect points wire (or trigger wires) and connect the Battery CD tester, according to the instructions on the back of the tester, and align rotor with a spark plug wire. Connect a spark gap tester to all spark plug wires and turn the ignition switch on. If the CD unit fires to only one spark plug wire, check points wire (for breaks and shorts) or trigger, If ANY other spark plug wire fires besides the one the rotor is aligned with, the distributor cap and rotor should be replaced, The Battery CD tester will fire the system to approximately 3000 RPM. If the Battery CD tester is not used, see related drawing below. If the CD unit fails to fire with this hookup, it is usually bad. Following the instructions included with the Trigger Tester, check the trigger to see if it is good or bad.
3) Engine cranks and fires as long as starter is engaged: This problem usually indicates a bad trigger.
4) Check the ignition coil: An open, cracked or poorly grounded coil can burn out a battery CD.
5) Check the DVA voltage on the primary input wire to the coil using the Fluke meter with the peak reading voltage adapter, or CD 77. The reading should be approximately 100 volts or more for OEM CD's, and 200+ for CDI Electronic units.
6) Inline engines with internal exhaust plate: If engine speeds up when you remove one spark plug wire, the internal exhaust plate is more than likely warped.
7) These tests can be performed on the bench or on the engine.
NOTE: Disconnect the trigger mechanism prior to testing!