Originally Posted by Culture Evil
I checked mine .. it seems fine, put a some lube on it...
Okay, once you take them out, they almost never work again. You should try a brand new QEV diaphragm before sending it anywhere...and when you put the new one in, don't lube it.
These things are picky. If they get too soft (from being lubed) the don't spring back properly. If they get too hard, from being dry, they don't collapse properly. If they've gotten sucked into the exhaust hole, or out of place in the exhaust pathway, they often get slightly misshapen and don't ever work right again. Try a new one if you have one, I think it will fix you up. If not, let me know.