I feel.like I'm doing the shotgun approach by replacing one thing at a time.
Yes, you are. Stop replacing parts and troubleshoot the problem.
You need to tell us first if its 12v or 6v.
These tractors are amazingly simple machines; they are over 70 years old and were designed to be maintained by the operator.
Some basic troubleshooting skills and a few common tools will get them running. Randomly replacing parts doesnt get you much.
Butyour friends (and maybe your experience) will often get in the way of fixing your tractor. Rarely are guesses like It's the coil helpful. We can make a long list of
possible causes for the tractor not running and start picking our favorite to check out. Or, we can step back and recognize that the trick to fixing these tractors (or trouble
shooting any piece of equipment) is to be systematic about it. You need to isolate the problem system by system, step by step and work from most likely to least likely and
replace parts only when you confirm they are defective. Jumping ahead to 'so-and-so said it could be whatever' or just replacing parts will waste your time and your money.
It takes three things for an engine to run: spark at the right time, compression, & gas/air in the right mixture. Compression is easy; check it with a gauge. But, you don't
lose compression overnight, so if your tractor won't start, or suddenly cuts off, forget about compression for the moment, & concentrate on narrowing the problem to fuel or
spark. If you don't do that, you are going to end up chasing your tail around that tractor & spending a boatload of money to fix what could easily be a loose wire or a clogged
fuel tank vent. I offer this advice from personal experience because I am not a magician. I do not have the magical ability to simply diagnose the problem & go right to the
fix. And I dont like playing guessing games either. So, whenever my tractors stop, I confirm both spark & fuel then go from there.
I might not be capable of telling you why your tractor isn't running, but I sure can tell you how to figure it out for yourself.
Bottom line: as soon as the tractor stops running, not 5 minutes later, check for spark, fuel and battery voltage.
Does the tractor have a spark that will jump 1/4 in open air?*
Will the gas drain out of the carb bowl in a steady stream and fill a pint jar in less than 2 minutes?
What is the EXACT voltage at the battery? ( yes, you need a multimeter for that, not a worthless light)
How do I know this part is defective?
These are the questions you need answered before you attempt any repairs or buy a new part.
*If you dont own a spark checker w/ an adjustable gap ( NOT a light) buy one. In the meantime, an old spark plug w/ the gap opened to at least will work. Ground it to a
rust & paint free spot on the engine turn the key on & look for a spark.
Amazon.com: The Best DealOriGlam Spark Plug Tester, Adjustable Ignition System Coil Tester, Coil-on Plug Ignition Spark Circuit Tester, Autos Diagnostic Test Tool :
Automotive
75 Tips