by ggoyeneche » Fri Aug 08, 2014 8:17 pm
Glad you were able to get it off. Usually older McLane's did not use allen screws to secure the sprocket to the intermediate jackshaft; rather they were cross drilled and secured with a roll pin. That's why part number 1053 is sold as a set, "Jack Shaft with Pulley and Sprocket".
Since the mower does appear to have a lot of miles (noting the wear on the rear roller), perhaps someone previous either replaced the sprocket with a tapped one (and allen screws) or drilled and tapped the sprocket to use allens.