The fuel pouring out was the needle being stuck open, if it ran OK for 20 mins it is probably free now, the throttle cable can be tightened by turning the screw on the throttle handle clockwise a bit of a turn this just gives a bit more tension on the control handle which is how it is supposed to operate. If you over tighten you will not be able to move it, the Victa Special is a 2 stroke, the smoke is more than likely the burning off of residue left through lack of use, this residue will be in the carby, the crankcase and in the bore and combustion chamber, 2 strokes are always smokey as it is the oil that is added to the fuel burning off, a good old mower I think I have a couple in the shed.
Regards Geoff.