Can anyone tell me where I can find this part. This is the plastic capped screw at the bottom of the stock carb at the bottom of the bowl that stops the gas from coming out of the overflow tube. My carb was leaking fuel all over the garage floor so I was tightening this screw and now the plastic broke on it and. Looking at all the different suppliers web sites and I can not find it. Not sure what to type in as far as a part description though as well. Any help would be much appreciated. In case year matters this is a 1984 z50.