Ok I am getting frustrated, The 20hp Kohler engine on my new walker is stalling out and dying sometimes. I'll be mowing along and the engine starts to stall, if i put the choke on full it will keep it from dying completely, but it won't even out. As soon as i pull the choke off, it dies again. First happened Friday, called the dealer in Wichita (hours drive) he said that it could be a bad diaphram in the carb. and it may be pumping the fuel into the engine and the oil. He wanted me to bring it to him as soon as I could. Took it to Wichita 7 am sat morning, ran it for an hour, even mowed their lawn with it, ran fine the whole time. Couldn't find any signs of gas in the oil. He changed the fuel filter and basically said that they couldn't do anything until it does it while he can see it. Take it home load it on the mowing trailer go to first job and mow about a minute and it stalls out!!! I call the dealer right then and he suggests I loosen the gas cap or swap it with one on my other mower. Possibly the cap is not venting, and creating a vacuum that is not allowing fuel to be sucked from the tank. Now it works fine all day until the last 5 min of mowing when it stalls out again! Here's something strange I found out, if it dies and I don't turn the key to off and just re-start it it continues to stall and won't run w/o the choke on. But, if i turn the key to OFF, then start it it will run fine, maybe for a minute, maybe 2 hours. My dealer, who has sold hundreds of these dosn't really have a clue what is going on. I think it may be the fuel pump??? Or something electrical that effects the fuel/carberation system?? BTW: I Do have fuel in the tank and I'm not mowing on any extreme slopes at the time, just flat ground. Checked the air filters and they are all clean. (only 18 hours on the unit). I'm just hoping that I don't have to take it back to Wichita again, not enough free time in my schedule to do that! I am calling the dealer first thing Monday morn. and telling him that it is still stalling and hopefully he can send someone to fix it. Thanks to anybody that has any suggestions!