Those are great, small tractors.
Bullet proof.
Generally, you should tell us if it's a gas
or diesel though in this case as the others
have said it's probably your ground cable.
Not uncommon to see one corrode inside where
the cable connects to the battery clamp.
Ground normally hooks to one of the bolts
that hold the starter in.
If you have a diesel I would spend the extra
dough for a Good cable - 0 or 00 wire size
and not the cheesy, cheap jobs that you get
at your local auto parts store.
Also, insure that your battery cables do not
get pinched behind the swing out battery
tray. There have been more Fords of that era
burn up from pinched battery cables than any
other cause. See photo.
Lastly, there is a Very Good Ford forum here
at Yesterday's Tractors.
Best to ask your Ford questions there.
nnalert the Ford Forum