Originally Posted by newz7151
... did you pull this engine off of something else and stick it on here? Your spring on the engine brake is still connected, so with that connected and no cable or other mechanism to pull it and release it, it's still riding up against the flywheel and acting like the engine brake should.. maybe you... had it wired open before and at some point your wire broke and fell off from the strain and you didn't notice it? take that big spring off in your last picture and see if it is still hard to start...
yes, I did stick a new engine on at one point.
It could be the spring because the mower started on the first pull until now.