yt 3600 Hunt and surging, black smoke and sputter on throttle up

[ray299]

Hunt and surging, black smoke and sputter on throttle up. Carb was dipped in cleaner, washed and blown out with air. Plug is black and sooty. Puffs smoke when throttled up as well as spitting and sputtering to get to higher rpms. Air box is clean. Linkages are clean. Seems like its running rich when throttle gets pushed to higher rpms but then levels out to sound like it runs fine. Any ideas?

[YamaDog]

is the choke adjusted right it should not come on until you get the throttle in the offset portion of the throttle

[Daffoml]

does the governor appear to be working?  Once my linkage was gummed up, and had similar problems, once I cleaned it, it ran better.

Also, heave carbon on the piston is a problem.  While running at full throttle mist water in (a normal plant-watering spray bottle is what I use) and that will make the black smoke roll while it burns it off.