Complete Loss of Resistance

This usually means that the clutch is not engaging due to the lubricant within the clutch becoming contaminated or dried out, preventing the clutch from engaging. In most cases this can be remedied by removing the flywheel and oiling the clutch. See instructions for removal steps:

Model C
FlywheelReplacement

Model D
FlywheelReplacement

Once the flywheel is removed, locate the clutch (which resembles a roller bearing). Apply a light oil (such as 3-IN-ONE® oil) directly on the rollers of the clutch. Reassemble and retry.
In rare cases, the clutch in the flywheel is worn out or damaged. If oiling does not fix the problem replace the flywheel assembly. Order a new balanced flywheel assembly: