Poulan Pro Walk-Behind Mower w/B&S STOPPED DEAD!!!

Well, I have read through several discussions on here, but none of them seem to have the answers I need. So, I apologize if this post sounds familiar. The Deal: I have a Poulan Pro Model#PR675Y21RHH Walk-Behind mower with a B&S 6.75hp engine. I was in the process of mowing the lawn when I hit a high spot in the yard and the mower just suddenly and abruptly quit running. Now, the high spot was only dirt and grass and obviously not the first time it's been mowed over, but it is the first time the mower has stopped because of it. Now the mower will not start at all . When I try to start it, I notice that there is ALOT of resistance when pulling the start cord. What I have done: I have cleaned the sparkplug and checked fuel and oil levels. I have checked the blade for blockage and bindage, there is none. I have removed the sparkplug and pulled the cord and it is still quite hard. I have removed the starting cord housing and turned the flywheel by hand (with and without the deadmans lever depressed) and the engine is still hard to turn. I have checked the engine brake and it is fully disengaged when the deadmans lever is depressed. I have removed the muffler and it is still hard to turn. I checked that the coil is not rubbing, and it's not. Now, when I say hard to turn, I mean just that. The engine does turn and I can hear the piston moving air, but with the sparkplug out and the muffler off and the brake released, shouldn't the engine spin almost effotlessly? I am just about at my wits end and ANY help will be greatly appreciated. I should also note that when the sparkplug was in, it didn't even act like it was going to start. No spit, no sputter, no nothing. HELP!!!!

 

When the mower stopped from hitting the dirt it probably sheared the flywheel key, however that doesn't explain the hard turning with the plug out unless the turf you disloged is stuck under the deck. With the sparkplug removed, try turning the blade and check ithe travel to see that the blade and crank aren't bent. If the engine tries to jerk the rope out of your hand you have a sheared key or the blade is not on. Have a good one. Geo

 

I checked the travel of the blade all the way around several times and I can see no noticable deviation or wabble either up nor down. If the flywheel key has in fact sheared, could a piece of it be binding on the crankshaft or something? It also seems that while the sparkplug is out, the resistance is about the same as if it were in and operating normally, not any less, and when the sparkplug is in the resistance is much higher. Where should I look and what do I need to do in order to check/change the flywheel key? Thanks