Looks like Mr. Mumbles was having the same problem with that pesky spring in the Walbro carb.
Just found this thread from a while back.
I’m not sure I left the spring in the carb last time I worked on it, if not, not sure I’ll find it again.
I would not have thrown it out, but where I put it is the question!
Anyway, time to go to the garage and have a look-see.
Mumbles carb…….

Old thread……..
https://www.aomci.org/forums/topic/walbro-carb-float-spring/