Mercury 1L2Z-12029-AA Ignition Coil Assembly

First of all, the coils should be wiped clean with a damp cloth and left to dry completely. Look for any cracks, damage or carbon tracking on each coil. Be certain that the coil fits tightly on the spark plug. Replace the coil if it is damaged. To get to the spark plugs, you have to take out the ignition coil, disconnect the electrical connector and remove the coil retaining screw. Pull straight up and out to remove the coil.

Thread the wire connecting to any battery terminal out of its negative holding place. Pull the ignition coil wire away from its connector. Each wire needs to have a label (tape) on it that says which cylinder it goes to, to stop mistakes during reinstallation. Pull the coil by removing its mounting bolt, lifting it straight up while unscrewing counterclockwise. Installation is the reverse of the removal procedure with the following additions: Before putting the coil into place, put a silicone dielectric layer over the whole rubber boot inside, then link each electrical wire to the right coil, making sure everything is attached strongly.

Mark wires and terminals with numbered tape for breaker points ignition systems. Remove primary wires and high-tension wire from the coil, then remove and clean the coil assembly. Check for cracks or damage and clean any corrosion. Use an ohmmeter to check coil primary and secondary resistance, replacing the coil if resistances don't match specifications. Reinstall the coil and reconnect wires. For breakerless systems, disconnect wires and measure resistance across coil primary terminals, replacing the coil if necessary. For EDIS systems, disconnect electrical connectors from the coil and check resistance between coil primary terminal and outer terminal. Replace the coil if resistances don't match specifications. To replace the coil, disconnect the negative cable from the battery and ignition coil electrical connectors, remove the bolts securing the ignition coil, and install the new coil.

After removing the old coil in the COP system, inspect the spark plug and check the coil harness connector terminals. Then, replace the coil and reconnect the harness.

To check the electronic integrated (El) ignition system with the coil over plug (COP) system, start by disconnecting the electrical connector(s) from each coil assembly with the ignition off. Use an ohmmeter to measure the resistance between the coil primary terminal (+) and the negative terminal (-). The resistance should match the specifications listed. Next, remove the COP assembly from the cylinder head and connect the ohmmeter between the secondary terminals, which fit over the spark plug. Again, the resistance should match the specifications. If the resistance is not correct, the coil should be replaced.

Clean the coil packs with a dampened cloth and dry them thoroughly. Then, inspect each coil pack for cracks, damage, and carbon tracking.

Remove the ignition coil mounting bolts and remove the coil from the valve cover.

After removing the old coil in the COP system, inspect the spark plug and check the coil harness connector terminals. Then, replace the coil and reconnect the harness.