Well, I finally bought a brand new Hustler Super Z, 35 hp, 72" VX4 deck. So far so good, except for one little issue. It backfires every time I shut it off. I let it idle down for about 10 to 15 seconds and it still does it. Called the place where I bought it and they said it might need to idle down for 30 seconds or so. I've never heard of it taking so long for an engine to "calm down" so to speak. Anybody else have this issue on their Super Z?