Hi guys, I have a problem with my Exmark Lazer Z with 27 hp. Hoping someone on here can help me out. The problem is the mower backfires after slowing down at or getting ready to go reverse. It does it more on a small grade lots, going down and getting ready to turn, almost want to stall then backfires. This backfire is unpredictable. Sometime it doesn't't backfire but want to almost stall out. It have stall completely a few time. I've replace sparks plug. Check the fuel pump. Check Air filter. Replace fuel filter. Taken carbuator apart to clean out any dirt or water that may be in there. Even put in higher grade gas (89) after shop recommended. I know most of us use regular. Everything looks good but still can't figure it out why it still doing it. I am running out of option and hoping you guys can throw me some ideas, thought, comment or anything. I'm starting to lean toward a bad carbuator because that my only thought left, that's why i'm here, i don't want to have to buy a new carbuator if it's something else. The engine have almost 450 hours on it. I must say, Taken the spark plugs out , It looks too lean (not getting enough gas). The gap is at 30 which is recommended. Again, please let me know what you think.