[jimcol]

Actually the flush king can help if it is a clog and the gate valve is open. Use the hose port on the flush king to run a plumbers snake, no head attached up the discharge pipe. If it dislodges the obstruction you'll get a little seepage out of the hose port but nothing like you would get out of the 3 inch pipe. You can even throttle down the hose port somewhat using the water flow valve on it. Helped a friend clear his obstruction using this technique but instead of a plumbers snake used a Teflon electrician fish tape.