I've scratched my head for a long time thinking the air slide on my 240 K-Jet is stuck, until I found out that it just needs a clean and is also supposed to slive very slowly from open to closed. It's a bi-metal strip with a heater coil. You can also tune it to idle faster or slower when cold by loosening the nut on the side and moving the slide in the direction you want. I've done that when I found a slide off a Japanese car (Mazda or Toyote or something). Just remember to stick a wire through the open slide before loosening the nut, else you might shut closed...