This model has an AutoChoke and manual throttle control, FYI....
Step 1. Make sure the engine is fully warmed up. If it is cool outside, (below 70) give the engine
at least 3 minutes with the throttle set to FAST to totally warm up. This absolutely critical on a mower with AutoChoke.
Step 2. Always
keep the throttle set to FAST when trying to engage the blade.
If the engine continues to die after doing the above, there is some problem, probably in the carburetor/choke, but just a guess. It is unlikely to be anything with the blade clutch, but that is remotely possible. In the event is is carburetor/fuel related, the engine speed must be checked with a tachometer to ensure it is running fast enough (throttle set to FAST) to handle the load of blade engagement. Without a tach, it can be impossible to know the correct engine speed. With limited mechanical skills and no tachometer, a dealer is the best choice to get this fixed properly, especially if you have warranty remaining. Please note, repairs required to a Honda mower that has decayed or improperly stored fuel are not considered factory defects and are not covered under the warranty.
You may wish to look for a different Honda dealer, but this time of year can be very busy, and the good ones will be backed up a bit. Try this link to find another dealer:
Find A Honda Dealer