Great job! Do it again 3X
How about the bowl nut/main jet?
The surging is usually from the small jets on either side of the choke butterfly.
What choke/carb cleaner are you using?
Any compressed air?
Might need a new gasket?
You are lucky it has the teeth on the flywheel! You can add electric start for about $50 including the two bolts to hold it on.