Working on my rough (or not) running WD again... Next steps:

So as you know from my posts here, my WD had been developing a slight miss when warmed up, and even then only rarely. Well then I was out plowing the garden and it started to miss and then it just started to run crazy rough. Had it back in the shop trying to retune the carb, and the starter bendix broke. So over the course of several weeks I got the parts and replaced that. So in the meantime I also took out the gas valve and flushed the tank, cleaned the sediment bowl and took the carb off and cleaned it out (it had some sand looking junk in the bottom of it).

So anyway, I go to crank it back over, and she only ever seems to start after you let off the starter and it starts to wind down (it seems to "catch" after you let go of the starter -- been doing this for many moons now). So I played with it for awhile, and it just kept getting worse. Sometimes it would start and idle for 2 minutes, sometimes for just 30 seconds, sometimes it wouldn't start at all, and opening the throttle up it seemed like it was going to die until the last second when it surged back. Seemed weak of power when pulling hills and wanted to die whenever put in gear and attempted to drive it anywhere.

Basically it's a 12V converted system. I have cleaned the carb, but didn't "adjust" anything or rebuild it internally. Playing with the idle adjust screw didn't seem to change anything about how the tractor was running, but cranking down on the main jet screw will kill her. Finally this last time I was working on it, it would just crank over but never start. I even pulled the air hose off the carb wondering if my air filter was plugged, but she still would just crank and not start.

Makes me think I need to check my coil, the resistor, the condensor, and the distributor. The only problem is... I don't know how to know if they're good or bad. Anybody have advice for easy ways to tell if these parts are bad? Corrosion build up? Worn points? Bad point gap? Where or how to measure the coil, resistor, and/or condensor with a Fluke meter? How to test the plugs when the tractor won't start -- or I guess if it will crank I should at least get spark -- right? I know when I was putting the starter back together I had to take a wire brush on a drill to clean up some of the corroded and rusty contacts -- perhaps I have a bad ground to my chassis? But the starter spins okay... I realize this is a long list, but any help you can give me is appreciated.

Shut the gas off at the tank.
Remove the spark plugs and check them for condition & gap.
Take one spark plug wire and put a spark plug in the end. Ground the side of the plug against a bare spot on the frame rail, or run a separate ground wire and alligator clip to the side of the plug.
In dim light, turn the engine over and watch for a good spark. The engine turns easily with the plugs out.
Try the plug in all four wires.
You will see if you have good spark. If you do, then look elsewhere.
If you don't, then change the condenser for starters.

Sounds pretty straight forward for the spark plugs. I will try that.

How about the distributor cap, how can I tell if I have excessive point wear or they're burnt up? Also, is there anything under the dust cover that I need to worry about? I've never gotten into this part of the tractor before.

You can basically test the coil the same way as you did the spark plugs. Pull the end out of the distributor and either hold it slightly above its hole or place it near bare frame and crank the engine, it should jump a spark. If not check to see if you have power to both posts on the coil when the key is on or you can unhook the wires from the coil and ohm for continuity. you should have one of three outcomes 1. No or possibly weak spark with high resistance/continuity-shorted coil-replacement needed. 2. No spark and no continuity- broken primary winding-replacement needed. 3. Spark and continuity-good coil. Obviously if you have no power to coil that is your problem. Points just require a good eye and a flat screwdriver. Remove and ground coil wire, remove cap and rotor. Turn engine over and look see if points fully close and then fully open to .020". If they do not close or they open more than .020" clean or adjust accordingly. You can spread the points farther than the .020 to see how they look. Both sides should be free of deep pitts, corrosion and flat. You should be able to clean them up with a flat screwdriver or emory cloth. Make sure to blow or wipe off the points to remove any contaminants. Condensors either work or they do not, in my experience they are the most common thing to fail in the ignition system. They are cheap and easy to replace. Resistors are similar to condensors, if the have continuity they are good, if not, they are bad.

Thank you very much for the tips. I will be working on this tomorrow (with my trusty volt/ohm meter), so I will report back with what I find out.

Yes Will, there ARE a few things to check under that "Dust cap"..!!

The Points should be Dry (no oil on the contacts) and NOT Pitted or Burned.

If they are, replace them.

Set the Point clearance with the small cam riding at the TOP of the highest part of the Distributor Cam.
Use a Steel Thickness Gauge to set the gap.

Be sure you re-install the Rotor Button, replace it if it needs it..
Clean the inside of the Distributor Cap to remove any dust or Carbon tracks (that will cause a Miss)..
GOOD Plug wires are a BIG Plus, too..

Ron.