automatic choke stuck?

[Beefcake]

My buggy is running very funny, its been popping through the intake I believe and I thought it was running lean since I have a 2'' Uni filter attached to 5'' of sink drain coupler. Well I pulled the spark plug and it was very covered and black. I think my automatic choke is stuck open and its running very rich. If I go WOT for more than 15 seconds it will back fire like 4 times and shoot fire out of the exhaust. Also, my paint on the frame near the exhaust tip has got black stuff all over it which is making me think its running rich. I'm gonna get another spark plug and try some different settings on the carb but I was wondering if there was any way to test the automatic choke? I have an extra carb w/ electric choke but I don't want to change it if its not necessary.

[olderthan]

thr choke works off electricity
do a search for elec choke
it will show you how to test

[Beefcake]

I put the new electric choke in and she is running like a top again, still back fires every once and awhile but not nearly as bad. Its still popping through the intake, but I'm hoping it stops when I get the right main jet in...

[BuggyMaster]

Back firing through the intake is actually an indication of a lean pilot jet. It is possible to be lean on the pilot and too fat on the main.