Remove the 2 socket head screws from the steering helmet. With a 1/4” 20 bolt about 2” long screw the bolt into one of the threaded holes in the helmet to back it out. Flip the helmet forward and remove the worm clamp on the bellows and the front clamp also then work the bellows forward. Remove the cover on the rear Of the drive, remove the cotter pin and clevis pin from the shift lever on the upper gear box. Remove the 2 front nuts and 2 socket head screws that hold the upper gear case then raise and rotate the gear case 90* and pull it back with the universal joint .
Then the engine should be able to turn.