Model and year please....
Could you please put your year and model info in your avatar, so everyone will know what your working on.
I would not be soaking the carbs. Take them apart, starting at the fuel pump (if your model has this attached). Clean everything on the inside, the internal porting and check valves with a can of brake or carb cleaner. The little red tube is excellent in getting to the small holes.
Then, flip the carb over to the other side. Take off the four screw head bolts and you'll expose the fuel chamber. The diaphragm can be gently pulled out. Careful not to rip it. Below it is the metering plate and jets. Remove the two screws that hold it on and you'll see the jets and the check valve ont the bottom of the plate......all this needs to be cleaned with the spray. Through the needle valve and seat, lever and spring assembly.
Look in my thread "snipes korner" (there is a link below) and you'll find a nice post I made on our carbs and some pix of the inside.........:cheers: