Having trouble getting the fuel level to stabilize on my Holley 390 carb.I have set it dry 3 times and lowered it so its a little lower than specs.Still getting too high fuel level when checking by using the site plugs.Thinking now I may have a bad float.Had a real good backfire through the carb when I set the timing 180 off.I dont see any damage to the float but how can I check without buying a new float?