Carb slide is not opening when the throttle is opened. Eng. starts revving then is choked down. Slide moves freely by hand. Acting like a hole in the diaphram, but there isn't one. Please post any advice on forum.

 

It will not open with the air box off.

 

if noone has messed with the spring it's not supposed to open . those type of carbs. need negative pressure(a lil vacuum) to open. you could try putting a finger or two or a lil duct tape across the air intake then peek inside while you're gagging it and it should open. you could try some some carb. cleaner on the slide too,just to make sure it's moving freely. check fuel pump and adjust valves

 

Check the lobes on the cam