Thermal Clutch Servicing
One of the causes of overheating can be a faulty thermal clutch.
The thermal clutch operates by the metal coil expanding and contracting with the temperature and subsequently operating a valve in the center. The valve controls the flow of a thick viscosity fluid to engage the clutch more as the temperature rises. Often this valve will seize up.
To fix it, simply lubricate it with WD40 or oil, and use a thin flathead screwdriver to manually to turn it and work it loose again.
If you want the clutch to engage at a lower temperature, you can pull the coil's tab out of the slot and rotate it counterclockwise to the slot on the opposite side.
