i amworking on a 350 big bear,it sputters and spits when you first get on the throttle and when you mash it over halfway it straighten out and goes.I put in a new carb kit,no diffrence.I soaked the carb in mean green for 4 or 5 days,no help.I then heated the mean green to boiling, then trasfered the boiling mean green to a homemade sonic cleaner I had made with a palm sander let it set for 3 or 4 hours with it running,put it all back together and still no change. I had a 350 bb I worked on a few months back that was running horrible ,I proabaly took that carb off at least 10 times,put a new carb kit in it also,to make a long story short,after about ten days i figured out it was the o ring on the choke stem.So on the bb im working on now that was the first thing i thought it mite be. He said it had been setting a very long time.Its like its in the low side of the carb to me.It doesnt cut completly out at low rpms just kinda sputters.DOES ANYBODY NO WHAT ELSE I CAN TRY??? I ran a fine wire threw every port and hole on it,used compressed air after every soaking and cleaning.. I just dont no what else to try..please any advice will be greatly appreciated.

 

does it run better when cold then warm??? what is your needle set at?? is your float set correctly

 

Most cases it's cause it's catching air somewhere, check for air leaks first before going any further

 

Fuel line clogged? Petcock gone bad?

 

Try turning your idle screw up a bit. Might be idling low.