There is an idle adjustment screw on the left hand side of the carb (throttle linkage side). Mine also used to run on when the idle was high, if its carboning up this can also cause run on, but I reakon lowing the idle should stop the problem.
The stalling under brakes etc. also happened to me and was caused by fuel level in fuel bowl being too high. Adjust the needle & seat to adjust this. To do this, you will notice a screw & nut on the top of each fuel bowl. Lossen the nut to allow you to turn the adjustment screw. Then remove the site plug on the fuel bowl on the right hand side of the carby. With the engine idling at running temperature adjust the fuel level with the adjustment screw until the bowl level is level with the bottom of the site plug hole. If fuel is just trickling out slowley this is OK. You will need to do this on both fuel bowls. Replace the site plugs and tighten the locking nut on each adjustemt screw.
This can be a bit of a messy job, especially if the fuel level is real high and fuel pisses out all over the place. Or if like mine (I susspect yours also) it rocks a bit at idle because of the cam.
I hope this all makes sense, but if you remove the air cleaner and take a look you will find the idle adjustment, neddle & seat adjustment and the fuel bowl site plugs.