Oooops - I think it's a Suzuki engine.

Try this: With carb apart, and float in place, turn upper part of carb, with needle valve and float in place,upside down. Peer at carb part and float. Gently raise the float to its limit. The measurement at the outer edge of the float, at the highest point of movement, is where you measure for float drop, which in this case will not be drop, but raise. I am assuming that you have the carb apart, and know it has a float!?

Thanks Rusty -

Had the carburetor apart a couple of times - most recently I figured out that the float drop is not adjustable at all. The drop is controlled by a plastic tang on the float - and that tang is not bendable or in any fashion adjustable (unless you want to snap that tang off - which would probably be very inadvisable). I am now playing with all the linkages. I've ordered two new linkages from Toro, as well as two new springs. Hopefully, I'll be able to figure out how they should be set (the Service Manual is not much help). My problem., I think, is with the governor/throttle linkage.