you can get an exploded diagram online from the parts section at CNH.. however.. to adjust the governor, you need a service manual.. either the aftermarket I&T fo-20, or the oem ford service manual. I'm surprised that since you own the tractor ( and a nice looking one at that ), and don't own the manuals needed to care for it. parts and service manuals will run you less than 100$.
PS.. what makes you think the governor is acting up? what's it doing?
Hunting? not picking up rpm upon load? over revving? no throttle response?
at least 2 of those have non governor related possible caused.. ie hunting can be fuel obstruction and sluggishness or lack of response can be flyweights in the dizzy advance.. etc..
soundguy