Yeah you definitely have to make sure EVERYTHING is clean in those POS carbs.. :hammer: Make sure the screens and tubes are all clean.. The tank and upper feed tube bowl is all clean.. Make sure the pickup tubes are not CRACKED somewhere because it happens.. Make sure the gasket is rite between the carb and tank because they have little dump holes and stuff, so if ya build your own, but don't build it rite, it won't work..
When you put your diaphragm in make SURE the face of the carb AND MAINLY that little cover are dead square nuts flat flush.. ALWAYS that plate gets warped from the screws being over tightened.. I like to just lay it flat on a good file and rub it till it's nice and true again...
Make sure all the passage holes are open and clean in the diaphragm cover... Make sure the TWO DIFFERENT flapper valve pockets will be sealed off seperately.. :doah: sometimes the plate is so warped that there is a gap between those two seperate chambers so they can't function as a one way valve like they are supposed to..
Uhhhhhhhhhhhh If the governor isn't hooked up.. Not hooked up rite.. fuel mixture isn't set quite rite..... When you accelerate.. Those OLDER carbs with a pull out choke, have such piss poor air flow, that you will cause the engine to cough out because the throttle opens faster than the carb can feed the engine.. :hammer:
Typically a briggs carb... the idle speed screw is two inches long.. BUT needs to be screwed in ALL two inches before the damn thing will idle fast enough to run.. :glare:
OH!! and a bad spark plug will LOOK like it's got good spark... BUT!!! will only run on like %100 fuel almost like it's dieseling until the plug is hot and 200 degrees from dieseling for twenty minutes whilst you pull on the rope and swear at it.. :angry:
Thats all that comes to mind off the top of my head...