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!