One man checking for spark at connection to plug?

[joltesvig]

How does one person check for spark at the plug connection?
Background: I backed my 31 out to go to a meeting last Saturday. I noticed the paint had some dust on it when I got it in the sun. I left it idling, running just fine while I wiped her off and put some Wesley's on the white walls. Still running fine, I jumped in, took the hand brake off, stepped on it, went 10 feet and the engine died without a sputter or any warning. I thought I ran out of gas but no. I checked for sticky float but there was gas in the carb bowl. So now I want to check for spark and would like to know an easy way to accomplish this since I am alone.

 

[31 A4door]

Pull the cap off and put the coil wire 1/4" away from the head. Turn the engine over by hand to where the points are open.... Turn the ignition switch on and then use a screw driver to arc between the points.. It should snap a spark every time you arc across them.

 

[Chuck Sea/Tac]

Pull your plugs, you may have sooted them up bad. If so just clean them up. Ive had that happen to me before.

 

[joltesvig]

Ok, thanks. I did that and there is no signs of a spark of any kind.
What would be a likely cause of no spark?
Anybody else have this happen, engine running fine and then quits without any warning because of no spark?

 

[Will N]

Could be that the high tension wire loosened up from the coil, cutting of the spark to all the cylinders simultaneously. Try shoving it back up. If only one plug went bad, more than likely the engine would not have stalled. It would have run, but badly.

 

[Mitch//pa]

Ck your fuse if you have one at the starter
Ck for 6 v at coil

 

[Mike V. Florida]

No Spark
Some possibilities are:
1.Blown or defective fuse (use of a fuse is an aftermarket item)
2.Bad connections at ammeter, or ammeter itself (t0 find out put a jumper wire from one post of the terminal box to the other to take the ammeter out of the circuit temporarily)
3.Bad ignition switch and/or cable, or loose cable connection at switch.
4.Loose or broken wires at bottom of coil
5.Loose or broken wires inside terminal box
6.Loose, bare or broken pigtail wire under distributor plate, or wire grounding to plate or distributor body
7.Points not opening, or point arm grounding to cam due to worn rubbing block
8.Worn electrode in underside of distributor cap
9.Loose or broken high tension wire from coil to cap
10.Condenser burned out or grounding (some condensers are too long and can touch the distributor body inside)
11.Weak coil
12.Rotor not turning due to loose cam screw or bad timing gear.


Ok now break out a volt meter (a light bulb can give false readings).
Start at the fuse block, you should have voltage on both sides of the fuse. If you only have voltage on one side, replace the fuse or fuse block.

Now with voltage on both sides of the fuse, move up to the junction box. There should be voltage at both terminals. If voltage is present only on one side the problem is at the ampmeter and you should Jumper the ampmeter for now.
You should have voltage on both sides of the coil. If not,
remove the red wire on the coil and check again. If you now have voltage on both sides, you have a problem further on. If the voltage is still only in one side you have a bad coil.

Open the points with a piece of paper and remove the condenser. Turn the key on and you should have voltage at the points.
Replace the condenser and you should still have voltage.

If voltage is missing, remove the top plate and check for voltage on the bottom plate.

Check is the connector from the ignition switch screwed in to far? Do you have voltage on the wire to the upper plate?

Is this wire shorting to ground or broken?

Remove the paper from the points and see that the points are closed. You should not have 0 volts at the points. If not,
The points are dirty or the distributor is not grounded well to the engine.