I have a 3.5HP Briggs Model 92909 Type 3912 01 Code 84012325. When I am pulling the rope to start it, at the end of the pull the engine grabs the rope and pulls back. I understand that one of the problems may be a sheared flywheel key? Is there any way to see if this maybe the problem without pulling the fly wheel? ( a lot of work if its not the problem) Thanks for your help.

will it start and sorta run crappy, not like it did before?? Did you hit something with it that would cause it to shear a key??

The mower has not been used for several years. I am not sure why it was not used. So far I have not been able to get it started. The rope broke so I am fixing it as soon as I have time. I do have good spark. The motor however kick back just at the end of the ropes travel. It will yank the rope out of my hands if I am not holding on tight. The motor has 70lbs of compression. Any sugesstion will be greatly appreciated.

I'd check it, I've seen em thrown out because of a sheared key..... and only a sheared key. Not much trouble while you already have the shroud off, and yes the best way to check it is by taking the flywheel off, some half way and just take the nut off, doesn't tell you right that way.

There are only two reasons why the engine pulls the rope out of your hand.One is a sheared flywheel key,as bugman has already mentioned,the other is a lose or missing blade.