it sounds like the starter clutch is binding up on the spindel on the end of the crank ,make shore this assembly is well oiled you note at the top of this an oil hole this has felt under it and is ment to be oiled at every service ,but I would pull it apart and make shaw theres no rust on it ,if so linish it of with emery cloth and oil it before you put back together this should see you right. good luck.
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