Coil is hot

[jack casey]

Tractor, Cub 102 has not run for 5-6 days. Today, I left the ignition turned on while working on carb adjustment, not running engine. That coil will give a serious burn.
I disconnected the battery. Know that coils can warm up in normal use but not like this.
Help please,
Jack

 

[lpalma]

The points were closed and caused the coil to overheat, is the bottom of it no longer flat?
When working on any cubs I always disconnect the neg battery cable.

 

[mgonitzke]

This is why the ignition should not be left on while the tractor is not running.

 

[digger]

Tractor, Cub 102 has not run for 5-6 days. Today, I left the ignition turned on while working on carb adjustment, not running engine. That coil will give a serious burn.
I disconnected the battery. Know that coils can warm up in normal use but not like this.
Help please,
Jack

Your lucky you didn't get this far, LOL

 

[jack casey]

The points were closed and caused the coil to overheat, is the bottom of it no longer flat?
When working on any cubs I always disconnect the neg batte

Thank you Lew. Coil is totally flat on the bottom, and, not to be boring that thing was frickin' hot. I lean toward replacing coil and condenser, what you think.
Jack

 

[kharvey]

I would bet the points are shot also.

 

[gary noblit]

Jack, if coil and points is it to fix you got a cheap lesson and how not to start a fire.I'm guessing you won't do that again...

 

[dfrisk]

Dad gave me three supposedly O-K Kohler coils about 18 years ago, He was cleaning up his shop for his last auction. They sat on my workbench for a year or two till one day I'm mowing my yard with my vacuum unit, it's ignition on the K181 runs off the '72's battery. And over the course of the afternoon I had all 3 coils fail, couple just stopped working but the one failed in a spectacular fashion, by shooting up a geyser of hot oil out the center socket for the plug wire. And yes, the points were ruined too. I'd learned years before that parts store coils generally won't work long on Kohlers, after 10-15 hours of run time they get hot and most frequently the engine just stops. BACK WHEN I had the 72 & 129 one Sunday afternoon they were BOTH sitting in the back yard waiting for their coils to cool. Picked up two new Kohler coils that week after work. I'm pretty sure those two are still working. I bought a Bosch Blue coil from Dave Kirk while I was building my Killer K321 years ago.
When I think about how many thousands of hours of run time my two FARMALLS have I couldn't begin to guess how many millions of sparks each tractor has made.
Back on 2006 SON and I spent about every weekend down clearing out STUFF for the auction in Mid-July. I took my 129 down planning to sell it with Dad's herd of Cubbies. The M with the loader was as handy as a pocket on a shirt moving stuff, until it started not running well. I brought 5 gallons of my own good gas for the 129, and used it to start fires, etc, and poured the last couple gallons in the M. The gas we were using in the M was so stale I couldn't start fires with it even clicking my BIC in a puddle of liquid gas. THE M was much happier with my gas in it's tank. My gas of choice usually is Kwik -Trip 91 octane Recreational gas, 100% lead-free, no ethanol. It's made specifically to use in stuff that sits idle, not running for extended periods.

 

[dkirk]

A simple remedy for preventing this type of failure - always take the key out of the ignition when the tractor is not running.

 

[jack casey]

The points were closed and caused the coil to overheat, is the bottom of it no longer flat?
When working on any cubs I always disconnect the neg battery cable.

I was not thinking, as I have a battery cut-off swt installed months ago and just forgot to use it.

 

[Jake Olsen]

I use the master switch every time I park even if I know I will be back on that tractor today or tomorrow. Grandkids love turning keys on.

 

[rfunk]

A simple remedy for preventing this type of failure - always take the key out of the ignition when the tractor is not running.

Yupp. Paranoid enough that I might forget to turn it off. Made my own SOP: when it ain't running, the key hangs with my hearing protection.

 

[jlord]

Isn't there a ballast resistor in the coil circuit to limit the current when running to prevent coil overheating? (direct connection with the starter circuit during cranking to give that extra "umph" for starting)
I know there are certain types of coils that can be used without a ballast resistor. I believe those would have a higher resistance value to limit overheating.

 

[1811Cub]

No ballast resistor or resistance wire on these that I am aware of.

 

[mgonitzke]

Kohler coils do not use a ballast.

 

[Greg Riutzel]

I believe those would have a higher resistance value to limit overheating.

Yes they do, 3.2 - 4 ohms. As long as the coil is in that range I've never had any get hot when running and the points last a long time.