Mike, if the belt has been slipping for a long time it is possible that it has worn the belt, and perhaps even the pulleys, like what happens with ride-ons that use a slipping belt as a clutch. Inspect the bottom of the belt, to see if it is shiny or shows signs of heat. If so, it is bottoming in a pulley. On the Greenfield it seems unlikely to slip on one of the big clutch-pulleys, but it could slip on the engine pulley.

I do not see how you could have moved the sliding pulley by tapping on a spring. You need to push the pulley itself, either with a small bar or perhaps with your foot, in the direction shown by the red arrow:

[Linked Image]

Of course if you use a lever you have to be careful not to damage the pulley, but large numbers of Greenfield owners do this more or less regularly with no difficulty.