Had an engine sitting around for a year or so. I put it on a bike. Well it has a pull start and centrifgual clutch(lots of potential trouble). Engine started easy and ran very well. Let the clutch out and nothing happened, engine didn't even bog. I assumed: auto clutch problem. Problem turned out to be the manual clutch. The pucks must have been shaped with a chainsaw and jamed in with a hammer. Reshaped the pucks and all is well!