A.C. D17 governor problem

I realize this post may be a bit long. I have a series II D17 that Grandpa owned, my dad owned, and now me. I grew up on a dairy farm and this was the only tractor we had for a long time so it got used every day. It started breaking governor weights in the late 80s or early 90s and I was an early teenager and dad thought I was a mechanic and commissioned me to work on it. Luckily we had a salvage yard close so parts were readily available. We changed front timing cover, power steering pump, made numerous adjustments, and the longest it went was a year without weights breaking. Easy to change, yes, but pieces getting in the pan clogging up the pump screen, pieces going through the gears up front just added to the frustration. I have no idea how many sets of governor weights it went through, but it was lots. Dad eventually retired the tractor as he had several others by then and I bought it from him about 10 years ago. Same trouble. Recently I had a cousin who is a machinist make a set of weights out of a stronger material and they're not breaking. But why the heck?? It rendered an otherwise great old dependable tractor very undependable. Then, like a flash I recently remembered something. Just before this problem started we took the front cover and pan off to fix an oil leak and the crank pulley was removed. Me being young and inexperienced didn't realize it needed the woodruff key in the pulley and hence it started to wobble. Wobbled for years and wore it egg shaped. Its rather heavy and I would guess it acts as a balancer maybe? You could even feel the vibration sitting on the seat. Could this have caused enough harmonic imbalance to break those weights? They're made of such soft material. It all happened in too good of sequence to be ignored. AS far as I know prior to me having the pulley off it never broke governor weights. Another thing, we always set the timing by ear and dad had a habit of advancing it too much and they would break sooner when he set the timing than when I would. I've fixed the pulley problem and it runs straight now. But too scared to try a set of factory weights. Im sort of attached to (dad nicknamed it "alley oop") the old tractor and I do some brushhogging with it so I would love to hear if anyone has had a similar issue...or think I may be on to something...cause this spans almost 30 years now and a lot of hair got scratched out. Thanks!

Broken governor weights are generally caused by: #1. weights being worn out and breaking thru a pivot pin hole. This includes loose pins and pin holes in the governor gear. #2. timing gears that are worn/loose creating too much backlash #3. incorrect "pinning" of the governor housing to the engine block causing too much or too little gear backlash to the cam gear #4. loose governor gear on the power steering pump shaft #5. camshaft endplay too great because no one adjusted the endplay setscrew in the timing cover #6. bent governor shaft from a previous failure and gears being chewed up. #7. any imbalance in the engines rotating parts. #8. tappet adjustment neglected causing the camshaft to not run as smoothly as it should. That's all I can think of. Do they break governor weights?? Yes, occasionally they do. Do they break governor weights multiple times like yours..........NO, not if they were repaired correctly. I oft times included new governor weights in a typical "tune-up" because I know they wear and with enough wear they can break. I know of hundreds of those WC-WD-WD45 -D-17 engines that have never broken a governor weight. So, it is NOT an everyday occurrence.

Dr. Allis, Thanks for the response. I understand it could be numerous things that could break them but what stumped us is the tractor never broke a weight for 25 years then when it started it couldn't stop. Gears got changed because of pieces going through them. Camshaft end screw got adjusted. Keys in the governor gear were replaced to make sure it was tight. RPMS were turned down. We would bend the governor arm to make it less responsive. Nothing made much difference.
Yes, my dad had a phobia of taking things to a shop and yes I was young and stupid. But we did ask around ALOT and NOBODY could give us a rock solid answer. Most said it was a vibration which made me think maybe it was the crank pulley. Besides we had no shop around that could or would have figured it out. I guess I find it hard to believe that everything has to be completely perfect when, like you say, all those tractors that have a godzillion hours and cant be entirely perfect and yet they don't break governor weights. I guess Ill never know. Wish I had the money to completely make that engine brand new but such wasn't the case back then nor now. I know if those governors could withstand a square baler hour after hour and year after year then they should also withstand things not being completely perfect or being "repaired right." Thanks.