96 micro, problems with crank shaft /centrifugal, and gearbox joining up

[jimb43]

hi guys, i had a micro engine cook on me so i went to a breakers and got complete engine for replacing. took the cooked one out (automatic)took the centrifugal clutch of and the thin kog it was fastened to the crank shaft , changed them over , fitted engine back together and the engine is stuck, won't turn at all , i forgot to place the thin piece of metal in between engine and box, is that enough to have the centrifugal stuck as it 2 mm closer. SILLY ME ?, any help here please
thanks jim

 

[frank]

it wont be that plate jim, the might have been an insert on the crank face tho ?