My Snapper with Kawasaki FJ180V will no longer start with the choke on like it used to.

The mower has the integral throttle and choke control. Push it all the way forward to close the choke when cold, pull once or twice to start, when it gets going, move the throttle lever back to fast position and choke opens.

Now when I try to start it with choke closed, there is a lot of resistance on the rip cord. It quickly floods the cylinder (smell fuel) but never starts. Pull the throttle back to fast, pull a few more times, and it starts. Requires 10 - 15 pulls when I used to be able to start this thing on the first pull.

I've disassembled and reassembled the carb no less than 5 times, the last time put in a new main jet and soaked all pieces overnight. Everything seems to be moving freely.

Any ideas? Could the blade have anything to do with it (running a Gator blade for the first time - more resistance?)?

Thanks.