Delco EST Ignition Wiring...
The Delco EST Standalone Distributor is a fully self-contained
marine electronic ignition system. Installation is not complicated, but setup of the timing procedure must be exact.
After the installation of the distributor and mounting of the primary coil, you will have a black coil pigtail with two black ends. This pigtail is marked "A/B" on the small end. This end goes to the distributor on the two prong connector marked "A/B". The other end is the coil side. It will plug in to the coil. On only one side, the second pigtail has a gray coil end with a purple and gray wire. The gray end will go on the coil on only on side. The gray wire is your tack lead, which must go to the gray wire on your engine harness. The purple wire is the 12 volt lead which will match the purple lead in your original harness.
Depending on the year and harness, there may be a resistor or a resistor wire in the system. Place a voltmeter on the engine harness, with the red lead to the purple lead and the black lead to ground. You should have 12 Volts or battery voltage. If the voltmeter reading is 10.9 or lower, you may have a resistor in line. Bypass the resistor and recheck the voltage. It should be 12 volts or system voltage. Connect the purple lead on the engine harness to the purple lead on the coil. Now you are ready to set timing.
Initial Timing procedures for EST
The initial timing connector is used to set initial timing of your Delco EST System. The initial timing connector is a 4 prong unit with white jumped and black lead. Secure this black lead to 12 volts and plug it in to the 4 prong slot on the distributor. This will lock the timing. The timing will not change with the RPM. Now with a timing light, set the timing to the specifications corresponding to the manufacturer's suggestion. REMOVE THE TIMING TOOL AFTER SETTING THE INITIAL TIMING!