I have an 88 model and first thing i did was rebuilt the carb and found the screw at the bottom on the side saw leaking and the drain would steadly leak so i removed the screw and looks like it has threads and then a tinny stem like shaft on it,, the shaft part was majorly pitted and would never posibly seat correctly so i replaced the O ring gasket the the screw and reinstalled it and the drain still dripped lightly so i just put a little rubber valve cap on it with a clamp, no leaks now for the last month!!! this may work for you guys.