bet the throttle body is black inside, but should be kinda bronze coloured. just warm up the engine, after taking the air cleaner lid off, hold it at about 2k rpm and spray inside the throat of carbie, motor will try to stall, stop spraying for a min, then repeat till clean, whats left of carbie cleaner wash off the outside of carbie.
and pcv valve and put it back in. after it cools off, look to see if the plate in carb is free, top one is choke. the little holes are the vents to float bowl, and idle curcuit, if you see raw fuel pouring/sputtering out of vents in carb, you have other problems in carb.
also can be a bad electric choke?
check vacuum line to dizzy advance, plugged in?
hope that helps mate
safety note, do not put your face over carbie, if it backfires, you will get a face full of fire