New Cub, No Spark, Hot Coil...

Mon Apr 29, 2013 7:02 pm

Hi, and thanks to those who kindly welcomed me to the forum. I brought my first-ever Cub home yesterday, and started messing with it today. The guy said he'd not been able to get it to run, so I bought a battery and gave it a shot. Turns over fine, seems to have compression. But apparently no spark. The push-pull ignition switch was pretty rusted and corroded, I just twist-tied those wires together to close the circuit. But got sparks when I did that. Then I tried, but no fire in engine. However, coil was growing hot, even when I wasn't trying to crank it. So, I'm assuming the coil is bad or it is grounding out somewhere. Can someone point me to a simple wiring diagram? I should point out, the wiring on this old Cub is very shot, not to mention it has a single wire dangling down from the wiring harness that I have no idea where to connect.

The wires running to dash are almost bare, coming out of insulation. Lights don't work, no fire anywhere. So... anyone have a solution, I'm all ears!

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Re: New Cub, No Spark, Hot Coil...

Mon Apr 29, 2013 7:52 pm

I should point out it is in its original configuration, 6v positive ground, no obvious alterations except that one wire hanging down appears to be a later addition.

Re: New Cub, No Spark, Hot Coil...

Mon Apr 29, 2013 7:57 pm

Start out my checking you points.

Wiring diagram, located in operator's manual for your tractor at top of page. Free down load.

Hot coil, again, start looking for the short at the ignition points.

Re: New Cub, No Spark, Hot Coil...

Mon Apr 29, 2013 8:06 pm

Ahhhh, that does make sense... Sorry, it's been a LONG time since I've messed with points. Haven't forgotten how, just been a long time, so my thinking is rusty on it. :-)

Re: New Cub, No Spark, Hot Coil...

Mon Apr 29, 2013 11:23 pm

For one thing, the housing of the coil needs to be grounded. Laying loose in a bent clamp looks like an unlikely ground.

Re: New Cub, No Spark, Hot Coil...

Tue Apr 30, 2013 12:42 am

Jim Becker wrote:For one thing, the housing of the coil needs to be grounded. Laying loose in a bent clamp looks like an unlikely ground.


Ahh, I was wondering about that. It is loose; no bolt in the holder. I'll dig in my nuts and bolts bin and tighten that up. Thanks!

Re: New Cub, No Spark, Hot Coil...

Tue Apr 30, 2013 6:20 am

I agree with Eugene about starting at the points. Also, check the insulator where the connector stud passes through the side of the distributor. The coil heating up is an indication that the distributor side of the coil is grounded, maybe as simple as a closed point gap.

Re: New Cub, No Spark, Hot Coil...

Tue Apr 30, 2013 6:31 am

Cool name "Dances with Cubs"....My wife and I chuckled over morning coffee....Dave

Re: New Cub, No Spark, Hot Coil...

Tue Apr 30, 2013 2:02 pm

pickerandsinger wrote:Cool name "Dances with Cubs"....My wife and I chuckled over morning coffee....Dave


:) Glad I could provide a chuckle!

Now I've REALLY got a problem! (No spark, hot coil)

Tue Apr 30, 2013 3:10 pm

Hoo boy... Not exactly how I planned my day to go!

Per the previous posts, I had a hot coil but no spark, even when I wasn't cranking the engine. 6v battery ignition. I pulled the distributor following the sequence in this thread viewtopic.php?t=14504 . Engine set to TDC, made a mark on the side of the distributor, pulled distributor, and before I could mark the gear it tumbled out, and a bunch of oil as well. In other words, I can't retrace where my distributor point was. To make it worse, though the points have some burned/arced areas on them, there was no sticking and they are opening and closing like they should, so I'm back to square one, anyway.

Anybody got a clue? Especially on how to get this distributor back in the correct place? :lost: :help:

Re: New Cub, No Spark, Hot Coil...

Tue Apr 30, 2013 4:14 pm

Now that you have the distributor out. With wire from coil to distributor not touching metal, turn on the ignition switch to see if coil gets hot. Coil gets hot - internally shorted.

Before you try to install the distributor. Multimeter, Ohms setting, points open, test for short at the wire terminal on side of distributor and distributor case. My guess is the points and condenser lead are shorted to the distributor case, with the insulator on the wrong side of points and condenser leads.

Before you try to reinstall the distributor, change out the points and condenser and reset point gap.

Accomplish above, then we can tell you how to reinstall the distributor and static time to engine.

Re: New Cub, No Spark, Hot Coil...

Tue Apr 30, 2013 4:49 pm

I love this stuff!!

They will have you fixed up and that Cub will be running in no time. :D

Re: New Cub, No Spark, Hot Coil...

Tue Apr 30, 2013 5:43 pm

Ah, darn, didn't know anyone had replied... I "think" I got distributor back in correctly. Had to back away from it a bit and think, but I realized I had what I needed in front of me: engine hadn't moved, mark on distributor body pointed the right way for the rotor to go, and mark on the case showed right way for the gear to go. So, I put it all back together. This time I put a new coil on it. After looking it over I could find no evidence of a short in the distributor, so I put the new coil in. THIS TIME I GOT IT TO POP! May have flooded it before it would catch, and by then the battery was drained. Off to TSC for a 6v battery charger. It's charging now. I'll have to postpone until a bit later, but hopefully I have some of the issues sorted out. I plan to pull the points and condenser ASAP and replace, since it is possible something underneath could be grounding out. There is still a short somewhere, but this coil isn't getting hot like the other one. One step at a time...