Hi guys, just joined your site from down here in Australia. I recently acquired a Greenfield rideon which is powered by an 11HP briggs ( model--253707 type--0169-01 code--86010211 ) my problem is it is contantly backfiring thru the carby and has no power under load. It will start and run but very rough and soon as you engage the blades backfiring gets worse and it will die. I have check the key on flywheel it's spot on---have relapped valves and checked clearances (.007 inlet---.011 exhaust )---have cleaned and checked carby everthing seems fine--airgap coil to flywheel .010-- pionts--.020--plug--.030---I'm running out of ideas--could it be the condensor or coil causing it to fire at the wrong time--would love to hear your input I'm just about over playing with it.Thanks Paul.:confused2: