[dmsfrr]

A replacement spring could be the simplest solution.
Depending on how it's working I'd be inclined to set it so it's just opened fully when warmed up, and when cold keep it running with your right foot.
If you were to change the carb to a different one it would be a 'whole can of worms' sort of thing.
A different carb will need... a new air cleaner, a different distributor, they'll work better with a newer intake manifold, etc. etc. ....
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