Interestingly enough, what I eventually found out was the REAL problem, was that leaving the choke on for more than a few seconds after it started was fouling the plug. I've been using the motor for several months now, and the routine I use is to pull out the choke, start it, then push the choke all the way back in immediately while turning up the throttle a little bit to keep it running. In short order the motor warms up enough that I turn the throttle back down to minimal idle, then when I'm ready, I head out.
Per earlier advice I got on here, when I'm done for the day, I unplug the fuel hose and let the engine run until the carb runs out of fuel, and I ALWAYS close the breather vent on the fuel tank when it's not in use.
Using these two methods, my motor has run flawlessly all summer - but then again, it IS a Honda!