Coil spark test?

Sun Apr 21, 2013 11:11 am

It's been a while since my last visit but I know the community has all the best advice. I am trying to bring my cub back to life after a long sleep (1 yr.). I got it started a couple times, and it ran ok but had difficult time restarting. I have since replaced the spark plug wires, distributor cap/rotor, spark plugs and now the coil. I am not getting any spark at the plugs, and am trying to determine if I have spark at the coil. Power is available at the coil (BAT side) when using a test light. Is there a way to test for spark at the coil w/o special equipment other than a test light? Thanks.

Don

Re: Coil spark test?

Sun Apr 21, 2013 11:19 am

Since this is a distributor, try to using a test light or voltmeter to make sure you are getting voltage to the point of the coil. If you are seeing voltage to the coil, then try going to the distributor side of the coil and see if you have any voltage readings there when points are open. You should see no voltage at all when they close.

Re: Coil spark test?

Sun Apr 21, 2013 11:19 am

Can I ask why you decided to replace the old coil?

Re: Coil spark test?

Sun Apr 21, 2013 11:22 am

Don, I don't see anywhere that says you replaced the points. If your points are glazed over you won't get spark. Try cleaning them with fine sandpaper or file or replace them.

Re: Coil spark test?

Sun Apr 21, 2013 11:30 am

@cubguy47 new coil ‘cause I thought old coil was shot. Maybe wrong about that now.

@Barnyard I have not ventured into the distributor yet, I don’t feel confident about my ability to monkey with timing issues. Is it possible to test for spark at the coil when it is not connected to the distributor?

Don

Re: Coil spark test?

Sun Apr 21, 2013 11:35 am

djhill wrote: Is it possible to test for spark at the coil when it is not connected to the distributor?

The coil gets its power from the points. If they are not working there will be no spark so you won't get any during a test.

Re: Coil spark test?

Sun Apr 21, 2013 11:50 am

@barnyard Thanks for the clarification. So if I want to check/replace the points will I need to worry about knocking the engine out of time? Manual says to get rotor pointing to cylinder 1, that seems easy enough, but do I need to remove the entire distributor from the tractor to complete this task? I do not seem to have a timing notch in my fan drive pulley and am worried I will have timing issues.

Don

Re: Coil spark test?

Sun Apr 21, 2013 12:08 pm

You don't have to remove anything but the cap to clean the points. The wires can even stay on the cap. Just put the cap back on the way it came off. With the cap off you can sand the point gap slightly. That may be all you need to get your spark back.

Re: Coil spark test?

Sun Apr 21, 2013 12:14 pm

djhill wrote:Is it possible to test for spark at the coil when it is not connected to the distributor?
Yes. Remove center ignition wire from distributor. Insert spark plug and place spark plug on good ground.

Disconnect wire on side of distributor. Ignition on. Touch terminal end of wire removed from side of distributor to good ground, then immediately remove. You should see a spark at the spark plug gap every time you touch and remove the wire - providing you have voltage through the coil.

If you have a test light or multimeter, test for battery voltage at the wire removed from side of distributor.

Re: Coil spark test?

Sun Apr 21, 2013 2:18 pm

Barnyard wrote:You don't have to remove anything but the cap to clean the points.


You also need to remove the plastic breaker cover under the rotor to get to the points.

If needed, and cleaning up the points does not work, you can also replace the points without removing the distributor, it is cramped quarters working in there with your hands, but it can be done. Take your time, follow the manuals. Good luck. 8)