I am troubleshooting a no-spark at plugs condition. A couple of months ago, I had a similar situation and had replaced the trigger assembly. Engine started and ran fine. Last week after running about 3 hours, engine began missing and after a couple of rounds of running and quitting, I got to a won't start and no spark at the plugs. I have performed a test of the switchbox and coil by disconnecting the 3 distributor wires at the switchbox and jumpering the white and brown terminals, placing a jumper on the black terminal and checking for an arc with the key on and the HV coil wire near a ground. When touching the black terminal jumper to ground, I get a really good arc from the coil wire to ground.
This points to the problem being in the distributor cap, rotor or trigger. Regarding the distributor: 1) I removed the brush/spring and cleaned the hole that it sits in and noticed that there is no direct contact between the spring/brush and the HV wire that screws into the cap. Accordingly, no continunity. 2) I repeated the above test, this time including the distributor cap, by using a jumper attached to the carbon brush inserted into the cap and checking for an arc to ground. 3) I was surprised, but I again got a nice healthy arc through the HV coil wire, cap/spring/brush to ground. Obviously, there is an arc jumping from the coil wire to the spring/brush inside the cap. Is this normal? Is there supposed to be an insert in the cap that privides a direct contact between the coil wire and the brush assy? I would appreciate some guidance on this before I move on to rotor and additional trigger troubleshooting.
This points to the problem being in the distributor cap, rotor or trigger. Regarding the distributor: 1) I removed the brush/spring and cleaned the hole that it sits in and noticed that there is no direct contact between the spring/brush and the HV wire that screws into the cap. Accordingly, no continunity. 2) I repeated the above test, this time including the distributor cap, by using a jumper attached to the carbon brush inserted into the cap and checking for an arc to ground. 3) I was surprised, but I again got a nice healthy arc through the HV coil wire, cap/spring/brush to ground. Obviously, there is an arc jumping from the coil wire to the spring/brush inside the cap. Is this normal? Is there supposed to be an insert in the cap that privides a direct contact between the coil wire and the brush assy? I would appreciate some guidance on this before I move on to rotor and additional trigger troubleshooting.