A
As that plastic gear turns faster and faster the centrifugal force causes those two flyweights to become heavier and heavier. Soon their weight will overcome the ability of the plastic's ability to hold them on.
uh nope!
the weights certainly do
NOT become heavier, they can't..
do not mix up force and mass.
the force increases (newtons as kg*m/s²) but that's thanks to increased acceleration (m/s²) , not because the weights get heavier (kg)
the flyweights themselves are not held back by the lever btw!
the lever is the "button" the expanding flywheels push
that tells the carb to close
and with a slowing down engine the springs in the governor contract the flyweights back again.
the spring on the lever is strong enough to help a bit maybe
but it's meant to bring the lever back to the now contracted push pin
on the governor shaft.
(to be pushed back again next time the weights expand and push the pin out)
there are many reasons the governor wheel can fail.
Most common (to us) are indeed excessive centrifugal forces.
Usually due to some jerk (literally [m/s³])
if it was a de or accelerating one can be seen on the governor remnants.
if the leading pin hole of a weight failed first it was an accelerating jerk,
if the trailing pin hole failed first it was a decellerating jerk.
(the pin hole that failed second is slightly stretched, the first one just snapped clean to pieces)
Anyways it's indeed always the pivot of the flyweights (the axle pin)
that fails first since that's where almost all forces act on.
once one weight broke free the imbalance and
new weakspot in the plastic gear
tear apart the governor wheel.
BUT even if the pivoting pin cannot break loose, the governor wheel can still fail
a slight imbalance can cause it to oval out at high speeds so it won't mesh properly with it's driving gear;
chewing off teeth causing a vibration that rattles everything apart
or causing the driving gear to perfectly hit on the tip of a tooth
causing an imperfection to crack open.. or or or.
The problem is:
we cannot prevent every situation that might or might not cause the governor gear to fail at higher speeds.
and it's quicker and safer to just remove that dang thing.
'sid