I pulled the carb off my 54 235 engine to rebuild it and one throttle plate screw was previously twisted off and the other was loose. So I gently tried to tighten the remaining screw and it twisted off too. I got one screw out but couldn't get the other out. Pretty small. Think it could be drilled out? Didn't know if these screws were even available . Maybe someone has an extra base laying around. Any suggestions?