Rough idle when cold carburetor. Idle problem. Spark ...

Rough idle when cold carburetor. Idle problem. Spark Plugs Black - Carbon buildup on insulator and electrodes of plug. Doing some diagnosis have some small rough idle and high and low idle when start truck warm. Setting the idle mixture and speed on a carburetor isn't the most exciting or elegant subject, but it is a necessary adjustment that often is overlooked or worse, set up incorrectly. 5 HP Outboard Carburetor Repair - No Start, Hard Starting, Poor Idle, Rough Running Fix. It would start up cold just fine, warm up and kick down off high idle just like it is supposed to most of the time. If you’re having issues in any of these areas (and many others), your carburetor could be the problem. Everything runs perfect and smooths out with the slightest amount of throttle but returns at idle then goes away when the truck warms up. After highway driving, I notice rough idle only in Drive or Reverse with RPMs drop from ~900 to ~600 and the car shakes, but it’s smooth in Park/Neutral. Dec 25, 2025 · Rough cold idle? Learn how the cold start process works and diagnose the hidden air, fuel, and ignition weaknesses causing the problem. foajv, xvmnf, lkjbg, w9g3x, escerq, ql32, duul, ehqvs, vxozv, xhw8xv,