8HP Tecumseh Carb for Coleman Powermate Generator

I have a older Coleman Powermate 4000 Watt Generator with a 8 HP Tecumseh engine. The carb has problems with idling - it backfires and runs rough. Gas also leaks out of the carb/ gas tank when it is sitting via the air intake housing. It has an idle screw, adjustment screw, and another screw on the bottom of the float bowl - not sure what that is for. What is that bottom adjustment screw? Can someone please tell me the proper adjustment settings for these three?? What could the leaking be from? I will also check the float for a leak as I read this in another post. Thank you for any and all help.

 

The carb needs to be cleaned and a kit installed. The needle is not seating.
The screw on the bottom is high speed adjustment. Both screws are set at 1-1/2 turns out from lightly seated.

 

Check your engine oil too and change it if it is overfull and smells of gas.

1 to 1 1/2 turns on the mixture screws are initial settings and should be fine tuned from there.

 

Thank you for the replies. I will check those adjustments again. I should mention that it did seem to run well when I cleaned and replaced the carb prior to connecting the "governor" linkage and it was just idling. After that it ran erratic and I keep on changing the adjustments. There was also some oil foam blowing lightly from an overflow tube from the engine. It didn't seem to be overfull but an oil change would probably be a good idea. I'll let you know how I make out.