Small Engines (Lawn Mowers, etc.): gasoline leak, gasoline leak, crank case

Question
B&S 12hp model 281707-0412 01 on Craftsman lawnmower.  Over few months, engine began running erratically, but would restart,  then finally wouldn't even fire.  I stored it in the garage until I could have it repaired (no rush), with appx 1 pint gas in tank.  After few days, found gas puddle on floor, and gas dripping from exhaust muffler. Opened cylinder head and found appx tablespoon of gas in cylinder head, and gas tank empty.  Drained crank case, got over 3 liters gas/oil mix. It had to be going thru gravity feed carb for months, so pulled float bowl.  Float was empty and no bubbles when squeezed under gas.  Rubber tip on float needle is resilient and not hard. How flexible should it be?  Is there any other way crank case could fill with gas???  Must be thru carb, no other gas connection.

Answer
You are correct it is the carb.  Most likely just a dirty inlet needle and seat or slightly worn needle/seat.  After cleaning the carb, replace the inlet needle.

Check your float to make sure it has no cracks in it and is not a "heavy" float.  You simply do this by putting the float in a bucket of water and seeing if you can see bubbles-this would mean that the float is taking on fuel- also can shake the float and hear if there is any gas inside of carb.

The fuel that you found inside of the cylinder is not a big concern.  It is all caused by the carb issue.