Original poster here. Quick update bought a can of SeaFoam a 3 way valve some fuel hose and clamps. Mounted the valve so can run from main tank, or from auxilary tank-SeaFoam or just run Carb dry.
Took a bit of cranking to get it to start with no fuel going in as the float bowl was full then switched back and forth between gas SeaFoam and off ending with letting it run on SeaFoam until can was about empty and Carb full. I let this sit overnight to soak everything with the SeaFoam.
Next evening went out and started again going back and forth between gas and off until it started to run and no more overflowing of the Carb, It smoked like the dickens for about 5 minutes then smoothed out and ran fine. I added a load to it and ran it for an hour and have ran it everyday since to test it for a few minutes.
I will run the Carb dry tonight and see if that works to eliminate the problem in the future.