Model # AKN Horizontal Shaft Size 2 7/8 x 2 3/4 Serial # 1996581 Sped # 63926 I did a valve job on both valves. and now the machine does not run and it pops thru the carby. Unit has a Blue Spark and has Plenty of Compression & fresh fuel but the unit will not start. It wants to but it keeps poping thru the carby. Any suggestions ? Please Respond. ThANKS.