cut to the bottom if you get bored with long posts, there will be the condensed version I purchased my 60" cut 23HP Kawasaki Hustler Z in July 2001 and was immediately impressed and in love with it, as I had been cutting about 4 acres of ground with a Yardman! I live in a very sloped and hilly area, and this machine outperformed several others on these steep slopes in the testing phase before my purchase, including a Bobcat. I am familiar with tractor roll-overs up close and personal, so this kind of safe operation was absolutely necessary and much appreciated. Anyhoo, on to the gist of my complaints now... Late last summer my Z started to show signs of sputtering. The only problem I had with the beast until then was a huge tendency for it to break the 1/2" deck wheel bolts (prolly 10 a year). The problem showed itself at first like a slight "miss" occasionally when pulling a load, and eventually, over a couple months, it led to "surging" at idle and complete failure while cutting 5" high grass after only a couple of feet. The sputtering seemed to only occur after the engine warmed up (about an hour of cutting) at first but over the course of that couple of months it got to the point of "fouling" from the start of the engine. Even without the blades engaged it would not pull my front yard (sloped) without dying! In that several month decline from occasional sputtering to eventually complete stalling, I went through a series of maintenance steps (and several tanks of gas), starting with the spark plug change, to air filter (and pre-filter), fuel filter, and changing out the fuel pump. When I could no longer cut grass with the Z due to poor performance, and had exhausted my technical expertise, I took it in October into the shop for a fix. They cleaned the carb and adjusted the coil pack and sent it back home. I only used it twice after that until putting it away for the winter, but on the second run it showed symptoms of sputtering again. I broke it out this spring and on the second run again, it began the same process as last summer (after running about an hour, like clockwork it began to sputter, and within minutes it would not cut grass without dying), so I packed it up and took it back to the shop. They thought I was nuts at first because they were not able to get it to exhibit the problem (despite their use of the mower to cut "heavy" grass for about a half an hour). But they were simply not cutting long enough to cause the problem to kick in. So, I took it home at their insistence, and the very same day that I took it home, after one hour of cutting, the problem appeared again as predicted! I took it back the next day and told them to let it run at idle for an hour then cut grass with it. They did this and still saw no problem supposedly. I then told them to let it run at idle for an hour and engage the blades for the duration of that time before cutting with it. They did not follow that prescription but instead, they let it run at idle for 3 hours, without the blades engaged, and then cut with it and discovered "the miss". They said they would change out the gas, the fuel lines, put dry gas in (because they suspected, and found, water), clean the carb, and adjust the coil pack again. After doing this, the machine stalled on them before they even took it out for a test cut on their property. They re-adjusted the pack and re-tested it by cutting some grass again(supposedly), and then sent it home with me. I unloaded it from the trailer last nite in the pouring rain(had been raining all day and wasnt about to stop), and it seemed to sputter several times (without the blades engaged of course) on the way to the shed. I understand (from reading on this forum, and talking to a Hustler customer service rep) that there was some kind of bulletin for externally vented carbs, and that this sputtering problem is not uncommon with Kawasaki engines, but I NEED MY MOWER BACK! Help! Symptoms: Surging at idle. Stalls and sputters after about an hours run, then minutes later, complete failure to cut more than a few feet.