720 gov fan/vent pump chipped gear

Well I ran into an unfortunate finding when I finally got the governor housing off the 720 gas crankcase. I found 3 chunks of the ventilator gear that mates with the governor gear. I was always warned that
this was a taboo area to mess with because of the heal setting these two gears mate together with. Ideally it would be nice to find a matching governor housing with governor assmebly to plunk right back
ontop of the crankcase, but I see steiner sells these parts PN AF2861R and F 3057R. See pictures of the chuncked out gears. I dont know how or if this tractor ran this way? Or if the previous owner broke
them while pulling this tractor that was stuck prior to selling it to me? Anyway most of the internals of the governor have some heavy rust on the drive/cam gears that will clean up, but Im not sure what
my options should be here with these chipped gears. I would hate to take my chances and run it this way-unless anyone has done so in the past with good results. I am leaning toward replacing them with new
but am unsure how difficult setting the heal up on these gears are? If anyone has any pointers I would appreciate it. Already too far into this tractor to give up now.

Fred, I didn't find the heel lash that hard to set on my JD 50. I realize that the 50 is a much smaller tractor, but the procedure should be the same. I followed the instructions in the service manual, setting the governor housing up in my big vise and meticulously adjusting the shims to get the proper tolerance. I think you would have some noise as the ''new'' gears wore in, but I'd rather have the noise than the chipped gears.

Good to know! Thanks! I have the manual and will read up on this again. The governors have been unchartered waters for me and I had never had to mess with them.

Never had any problems with noise, so get what you need and put it together. I never worried about the gears matching. Only noisy gears I have found was putting a new gear on the topshaft of a 4020 transmission, but just did what the customer wanted. Funny that he made a comment about the noise, thinking he was gonna get a free repair, but pointed out to him that it was the gear we replaced. That was 15 years ago and he still calls for repair work.

The general rule for bevel gears is to adjust for backlash and keep the outer machined surfaces of the gears in line. Adjust the shims on the governor shaft to get backlash and shim the fanshaft till the outer surfaces match.