I picked up a Yard Machines edger with a 3.5hp 4 stroke motor.  It is very hard to pull start, like the compression is so high I cannot spin the motor enough to start it or even see if I can get spark, fuel, etc.
 
What could be causing it to be so hard to pull?  The operator handle seems to be working fine to release the motor so I don't think that's it.  
 
Any suggestions are appreciated!
 
Dana

Might disconnect the engine from the edger to narrow down the issue to the engine itself..
 
 

That edger was most likely was sitting and its almost locked up. Take the spark plug, carb, muffler, off. Then spray bp blaster in the wholes.Wait for the bp blaster to work ( for like 30 minutes) Then take a big flat tipped screwdriver and put it along the flywheel so it is sitting inside the flywheel fins. Gently start going back and forth. Also drain the oil. Keep doing that once it is free enough. Put everything back together. Make sure you get all of the bp blaster liquid out. Then rebuild the carb. Or this is what i do. I tie the shut off bar down to the handle, Then i spray 2 plus 2 in the carb with the choke on. If it starts but dont stay running install  then buy an after market carb on Amazon. Watch some youtube on how to free up your engine and how to put your carb on. Good luck and remember safety first. Always unhook the spark plug wire before working on any small engine!!

Pull the starter cover off and physically make sure the safety (if equipped) brake IS pulled away from the flywheel...
 
Posting an engine MODEL # here helps others find exactly what type engine you have.
 
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I have the same issue with my cheapo yard machine! And once you do get the motor free, it'll rip your arm off even when it does rotate. I'm not sure what is up with these edgers. Mine is a vertical shaft with a belt to turn the edger blade and I got it to start by cleaning the spark plug.