Depending on what barrel you are using would require an adaptor or not for using the G4 / LM carby,
I think the plastic manifold flange connector can be stuck on with JB Weld.
Back to the G2 tomkatoz ,I would first check if the flag shaft is excessively worn by trying to push the flag from side to side ,if there is movement this can cause the gears to strip or disengage meaning no throttle control. ( like in the pic below)
If the carby is still leaking out the primer shaft or overflow orifice then the needle and seat are not shutting off, the primer rod could be corroded causing the shaft to not fully seat up the shafts hole ,you may need to clean the primer shaft or work it free with wd40.If this is the problem like in the pic below the stuck primer rod stops the float rising to turn the fuel supply off.
I would also blow through the two main jet supply ports just to know there are no blockages.
To test if the needle and seat work you should be able to blow air in the fuel line connector while holding the needle in with your finger or a small screw driver if air is blowing through then the needle and seat are leaking and need replacing.
If the governor gears are not working ,the cheapest option would be to replace the carby.
