Briggs and Stratton 190cc 128m02-0017-f1

Hello everyone I had to replace the oil sump on my toro 22 recycler. I replaced the oil sump the pan gasket and the crankshaft oil seal. I made sure the timing marks lined up reinstalled the governor and the oil sump goes on easy no problem. My problem is after I mount the engine back to the mower I can't pull the pull cord. I removed the spark plug still nothing. Any ideas of what might be causing this issue. I've removed and checked everything 3 times with the same outcome.