First off, dress the points w/ card stock or a clean dollar bill. New points often have an oily residue on them.
Assuming that the bushings & advance weights are ok, the most common electrical failure (no spark, weak spark) points on the frontmount are:
1. The insulator under the concave head screw.
2. The insulator at the end of the points where the copper strip attaches.
3. The copper strip grounded to the plate.
4. The condenser wire grounding.
5. The pigtail/tab not making contact.
6. Incorrect positioning of the spring clip on the plate causing the pigtail to ground.
7. Incorrect seating of the coil on the distributor.
8. Water/moisture inside the cap due to gasket failure or the absence of a gasket.
Coil problems are difficult to diagnose. For starters, round coils are pretty robust & square coils aren’t, but neither one will hold up to a poorly done 12v conversion that allows too much current to the coil. There are a few ways to see if a coil is bad, but it’s not possible to determine if a coil is good w/o some expensive testing equipment. If you detect a dead short or high resistance in the coil w/ an ohm meter, it’s bad. If it’s cracked, it’s bad. If a sidemount coil w/ battery voltage to the primary will not jump a ¼” gap from the secondary wire to the block, it’s bad. But, here is the hard part: even if you do not detect a short, even if it will produce a spark, even if it’s not cracked, that doesn’t mean the coil will work when it’s hot & under a load. So, it’s a process of elimination. If the tractor starts & runs fine for 30 minutes or an hour then cuts off & refuses to re-start, and you checked for spark at the plugs & it had no spark at all, AND you jumped the resistor (if it has one) that’s a good sign that you have a bad coil. Let it cool off, restart it & if you have a good spark, odds are it’s a bad coil. But, even then, you might end up w/ a spare coil on the shelf!
Bottom line.....coils don't go bad from old age. They go bad from getting too hot thanks to too much current.
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