The maintenance folks at Three Wing report that N631S has been run up, no leaks observed, ops normal. The cowl is back on the airplane and the airplane is back on the tie-down.
When I stopped there this morning the carburetor float had already been replaced and the carb was back on the engine with all of its sundry hoses and cables back in place. So:
The old float is a brass assembly with brazed buoyancy chambers. It shows some wear in the shaft clip area and in the tab that actuates the float valve. The float is date-stamped "8-84" making it 25 years old.
I didn't see the new float but I am told it is a bit smaller and made of some sort of blue polymeric material (perhaps a closed cell syntactic foam). Here's what the old brass float looks like:
The oil has been changed and N631S is good to go for the weekend trek to DC.