coil

[Todd]

Trying to get it started. I have 12vlt to the coil but no spark from the coil wire. Bad coil?

[Cubnut]

Not necessarily. The points complete the circuit by forming the timed intermittent ground path...if they're bad, you'll see voltage at both primary terminals on the coil but still get no spark. The condensor is in the same path and can easily be involved as well.

Check it again and turn the engine over slowly by hand. If the points are working, you'll see the coil voltage disappear regularly as they close and reappear when they open. Be sure to disconnect the coil lead to the distributor cap before trying this so the engine won't start. If the voltage at the coil terminals stays steady, check the points & condensor. If it makes & breaks like it should, plug a spark plug into the coil hi voltage lead and ground it...cranking should make it spark. If it does, you probably have a problem with the cap or rotor.

Beware of a bad coil hi voltage lead. It can make you think the coil is bad.

[WKPoor]

You gotta collapse the primary windings to generate current flow in the secondary, take a look at the points and condensor, somethings probably wrong there. Bill

[Todd]

THanks will do, This tractor ran, i just got it painted, last year had new point condensor cap and rotor. but it has sat for a year.

[Bigdog]

Todd, you need to check to see if the points are opening and closing.
the coil terminal that goes to the distributor should read zero volts unless the points are open. The easiest way to find out is to pull the distributor cap off and look to see if the points are opening as the distributor shaft turns. If they are, put the voltmeter lead on that coil terminal and crank the motor over by hand to see if the voltage is there intermittantly. It could be that the points are glazed over and not making contact (will have voltage on the coil terminal all the time) or the points are not opening or the condensor has shorted out. If the points and condensor check out OK and you still don't have spark from the coil then it is likely bad.
Another quick check is to take a screwdriver and with the switch on, pry the points open and let them close. Each time you do that the coil should produce a spark.

[Bigdog]

Dang! I must type slow. There was no response to this post when I started typing mine!

[Cubnut]

LOL! You're not slow...we just typed faster!

[Todd]

ok. here is where i am at

12vlt to the coil. turned the engine over points open and close. when they are closed I get 12 volts to the terminal between the dist and the coil. when they are open its open.

[Todd]

OK I LOVE you guys!. sanded the points off with a little 600. runs like a top!

[Cubnut]

Good job, Todd! I love to hear that a Cub runs great!

I had a friend who had a running engine. He did a tuneup that included no parts replacement...just cleaned the plugs and set the point gap. He used a brand-new feeler gauge, and it still had the factory grease on it...the grease got on the points and kept them from making contact. Three days and 45 dollars later, he finally cleaned the points and it ran beautifully.

And he was a professional mechanic.

[Russ Leggitt]

Hi Todd & Big Dog,

Looks like another case of varnish on the points. Todd, I put in a new
set of points in one of mine recently and nothing. Double checked everything I could think of, even looked at the "NEW" points and with
Big Dog's and others help I went to checking the circuit at every point
along the route and low and behold the points had what appeared to be
varnish on them. I burnished then and bang, GW fired right up.

[Todd]

Rebuilt the carb, and fixed the Dist, NOT a bad days work. Just have to print a few sticker and paint a few small parts and I'm done!