I find a lot of people leave the throttle in the off position after turning the engine off and this compresses the outer
spring and it looses it's tension after time and won't open the poppet valve so you need to pull the spring out
and stretch the spring to a decent length again.
Sometimes the diaphragm stops the poppet valve reaching full throttle so with the carby off and setting the throttle to full throttle
I use long nose pliers to pull the poppet to full throttle while the back of the carby is off , then while you are holding the poppet
valve open put the back outer spring in and clip on the back cap.
Cheers
Max.
