Don't trouble shoot the screwdriver condition. Trouble shoot the condition where you turn the ignition key.
Does the engine turn over noticeably slower with the key than with the screw driver?
To answer your question. I had to disconnect the dist to get a solenoid reading because it starts up too fast. Ground on engine, solenoid read 9.8 volts. Lower than I expected, but has never been a problem and never had reason to check.
If you are getting a spark and fuel and it cranks, then there is something about the info and the conditions that you are giving us that is either inaccurate or somehow not in sequence that allows us to see the picture.
For instance. You say when you crank the engine over with the key, you are getting 12 volts at the distributor and a spare plug on one of the wires is sparking, yet the engine does not start. You now get out of the truck leaving the key in the run position and with a screw driver it then starts. You've given no indication that it was starving for fuel earlier and now fuel has been pumped into the carb. You have not indicated that the engine cranks faster with the screw driver than with the key. If the plugs had been fouled, they did not clean up instantly. Is the voltage at the distributor now greater than it was before? Are you now getting 12.5 or maybe 13 volts at the distributor?(from a 12v bat delivering 250 amps to the starter) Is the spare plug (what) still firing?
Condescending or not, 12volts at the coil and no start when cranking with the key doesn't work for me. It's either bad meter, bad ground or bad information gathering.
When you do start the engine what is the volt reading at the dist??
