Most likely the valves are too loose... If they get too loose the Compression release lobe on the cam will not have any affect and the engine will snap back the pull rope on the compression stroke...... Seen it a million times, it is really bad on the Vangard OHV engines Briggs has, but not uncommon on the Tec Engine too...
Let me know what you find...
If I understand the above right the sparkplug wire can be removed and pullback will still happen. That pullback would be from compression only.
It's been a few months since this happend and I just got to the engine today. I think it was probably pulling back for both reasons, compression and timing. I could pull the cord with no gas or spark and get pullback but at times I would get a fire can pullback.
The valves were .011 intake and 0 exhaust. They got set at .005. Pulling was then normal with the plug wire out. I thought I was in there. With gas and spark connected it was hard to fire but when it did it always was a single put and pullback. So I think the compression pullback was cured but the timing pullback still there. I'll probably pull the covers tonight.
If I did not read your prior post I would have bypassed the valves and gone right for the flywheel key. If it's not the key I'll be lost as I'm pretty sure this thing has SSI.