Small Engines (Lawn Mowers, etc.): 5.5 powertrain engine, internal passages, flywheel

Question
I have 5.5hp powertrain gas engine that won't start. Last fall it stopped and i can't start it. Gas got into the oil so i changed that.Took the bowl off to check the needle and seat, it seems to be fine. When i push on the float, gas comes out. When i pull start it, it backfires through the muffler and won't start. Any idea what to. thanks

Answer
You said you checked the needle and seat by actuating the float by hand but you also need to check if the float is saturated or full of fuel if you haven't already.  You should also thoroughly clean the carb, which includes pushing a piece of tag wire through all of the internal passages and following up with aerosol carb cleaner.  If you still have a no start condition and it is backfiring through the muffler, the issue could be a sheared flywheel key.  Let me know what you find.