Re: 73 115 V4 only 2 cyl. getting spark
Welcome to iboats.
Following is from the CDI troublehsooting matrix.
First check the timer base’s resistance from the #1 to the #3 sensor wire, and from the #2 to the #4 sensor wire. Reading should be 10-20 ohms on each set (or 30-40 ohms for CDI Electronics Blue Timer Bases).
Then check the DVA output from the timer base. A reading of at least 0.5V or more from the #1 to the #3 sensor wire, and from the #2 to the #4 sensor wire (while connected to the pack) is needed to have spark. If the output is low, you may try to reset the air gap between the timer base sensor and the triggering magnet using a sensor gap gauge or by using the following method:
a) Loosen the two mounting screws on the sensors and the nuts located in the epoxy on the outside of the heat shield of the timer base.
b) Slide the sensors in toward the crankshaft until the sensor touches the stop boss located at the base of the sensor mounting area. Tighten the mounting screws.
c) Coat the face of the sensors with machinists bluing or equivalent.
d) Install the flywheel without the key and rotate the flywheel at least one full turn.
e) Remove the flywheel and check to see if the trigging magnet struck the face of the sensors. If it did, back the sensor out approximately 0.005” and repeat steps c, d and e.
f) If the ignition fired, finger tight the nuts on the outside of the heat shield and coat them with RTV.
