My totally stock '98 200 ran very similarly to yours. After I started it, let it warm for a little while, and took off for the first time, it would bog and blow epic amounts of smoke. After a few seconds of this it would clear and run great. Once it was good and warm it ran great as long as I was gassing it and not lugging around. If I did putt around, even for just a little while, the next time I opened the throttle...epic smoke.
My first thought was that the pilot circuit was super rich. I opened the air screw a bit at a time until it was out over 2 turns. This actually helped quite a bit. Evidence that the pilot jet needed changing. I took out the stock (#48) jet and changed it to a #45. Big improvement, cured it in fact. I had to mess with the air screw a bit but I found the proper setting quickly. Snappy response off idle and little to no loading up even after lugging for extended periods.
That's all I did to the carb, I haven't messed with the main jet because I don't see the need.
Good luck,
Matt