Could my coil be bad? KT17 series II
 

My 682 starts sputtering and dies after about 20 minutes running, the coil gets too hot to hold on to. Once it cools down it will start up and repeat the cycle. I know with my old farmall tractors those symptoms mean a bad coil. Is that true with these dual output coils?
How does the coil know which spark plug to send the spark to or does it do both plugs each time? Just wondering and thanks for any input.

I would say the second this happens when it starts to sputter ohm it out. It may not go to zero ohms when it happens. You could ohm it out cold when it's running ok. Then compare it to when it acts up and gets hot. The manual may have the spec in it but I'm not sure

Edit. You need to check both primary and secondary resistance. I would think secondary should be up around 10,000 or so and primary in the 3-5 range

It is a wasted spark system,
inasmuch as it fires both plugs @ the same time.
Some guys use a $30 or so Hardley coil, instead of a $100 klub kadit koil :biggrin2:

yup I have put a Harley coil on one of my KT's and an NOS OEM K482-532 Kohler coil that I discovered laying around, on my other. Both run great.
if you get the Harley coil get the "6 ohm" one, I think thy list for up to 1979.
the newer ones with electronic ignition are only 3 ohm, if you wind up with one like that, just be sure to add a ballast resistor into the wire going to the "+" side.

Thanks you guys I ordered a 5 ohm chrome one for 50 bucks that comes with new plug wires. By the way I noticed the old coil is swollen and rounded on the end, maybe from getting so hot?