Back Plate

The Tiger back plate assembly must be correctly installed to ensure that the propeller drive lugs in the crankshaft are correctly lined up. Since the common spinner change to the newer "Globe spinner installation" referenced in the Type Certificate (consisting of Bulkhead Assembly Aft 5506008-505, Bulkhead Assembly Fwd 5506010-503, Doubler 5506011-3 and Spinner 5506009-3) the propeller drive lugs have only about 0.060 of an inch protruding into the rear of the prop spacer...

This is a common failure mode caused by incorrect propeller installation...

Have a helper hold the spinner backplate tight against the crankshaft drive lugs while the prop and spacer is being bolted on. Keep holding it in place until the prop bolts are snugged down.