4 cycle 6.25 hp won't start. Cold start reservoir has gas in it after priming. Have cleaned it three times. Spark plug is a j19LM brand new. At this point I am stumped. Mower model number is 10355. Serial number is 9918111. Engine number is LEV120 361043B (D). What am I missing??what else should I look at and or do? Not the smartest mechanic but will work through it. Thank you