slow jet can get clogged with ease and ive had first hand experience of it,3-4 times in a week.problem was the float was not set properly by mechanic when i had my carb serviced.so when car was running on CNG,obviously there wasnt any petrol in float chamber,so float hung freely and was actually touching the chamber base,which was causing it to dissolve due to excessive heat..and when i'd convert to petrol,that debris would clog up the slow jet causing all sort of problems. so i opened up my carb my self at home,after alot of tries,set the carb perfectly so that it wont touch the base when float chamber is empty.so try checking out for the said problem too.might come handy for you.opening up the carb is not an easy job,but ive seen it being opened by mechanic 2-3 times and now i can open it my self and do a little cleaning myself.but i'd suggest you to go to the mech,and check for the problem i had.and yes the slow jet is just on the top,so if problem lies,whole carb wont need opening,all that needs to be done would be taking carb off the car,open up its head and voila,there is the slow jet
