Yeah the throttle cable not moving the throttle valve (butterfly) in the carby is normal in the G3 from memory, all the movement is really controlled by the black plastic governor vane. The throttle cable adjusts how much the spring tension is against the governor vane. They revert to full stick/wide open and rely on the governor vane and magneto air pressure (don't ask me if its positive pressure or vacuum, I cant remember) to close it/reduce RPM. Engine slows, throttle open up more, engine revs up vane moves and closes throttle to slow RPM, governs the engine at the set RPM. Could still be too much tension, another thing that can happen is the the bevel tooth drive arrangement that drives the butterfly inside the carby can be damaged. I have also seen the governor vane jammed and or forced behind metal work in the cowling. As far as tension is concerned from memory its stuff all. If there is a fair bit of spring tension against the vane when you move it with your hands the air pressure changes in the cowling caused by the fins and engine rotation have no hope of moving it, a Victa ain't a Boeing 747
(not that much suck or blow)
Another thing to note is that this older version of the engine doesn't have o-rings but has rubber/neoprene oil seals on both ends of the crankshaft to seal the crank case, they are like the o-rings in the respect they need to work.
Have a play with the carby governor first, you should be able to see how it all works fairly easily by looking at it and a bit of guess check and improve, if you have too little tension on it, it probably won't rev much at all, no biggy just add more, whats the worst that could happen?
Good luck!
David
