Choke is and has always been used for cold start and we have tried not using it but no success with that. Fuel flow is not the problem ignition seems to be the issue. (It will flood if you keep trying too long with or without the choke.)
Correction to Engine Plates contain the following Family 1HNXS. 6712AK Stamped number on block has QAFM GJAC - 2007264 On the Red Plastic Flywheel cover ACN006 662 862
As mentioned the problem began at least 4 years ago. It began with the second use of the year. In fact the strange thing is that each spring it will fire up fine the first time you try to start it and then the problem begins after the first use. When it started I checked all the parts I could readily check, plugs, plug wires, gas filter, etc. Nothing changed the routine. Once the engine has been started for the day it will fire up readily. Now the problem pretty consistently unless the weather has been very dry with no dew or rain for at least a week or so. Very consistent issue if the weather is damp or we have a heavy dew after the mower has been used.
Please read customers response before asking for clarification. I stated that the engine would flood if cranked too long indicating that FUEL flow is not the problem.
The problem is clearly ignition related and in fact I solved it no help from you. I called the original selling dealer who had a very qualified mechanic who explained how the problem might be caused and after spending $4.00 for a spark check I found the issue and fixed it thanks to the mechanic who answered my question for free.