Doesn’t Idle Well
You could have 1 of several problems. We will list some of them here.
- Check for vacuum leaks.
- Check for free play in the throttle shaft. If loose, then you may get a rough idle due to a vacuum leak here. Spray carb cleaner around the shaft. If loose the RPM will probably smooth out.
- Remove the idle mixture screw and blow out the hole. At the same time check to see if the idle transfer holes are open. If the idle mixture screw is grooved, then replace it.
- Abnormal turns in the idle mixture screw indicates a problem and it may not be the idle mixture screw itself.
- Check to see if the idle restrictions path are clear. There are two as you can see in the illustration.
- Any leak around the mounting gasket may be due to not flat flange condition. Run a flat file over the surface until flat.
- Is the choke valve fully open when the engine is warmed up?
- Fuel bowl vent valve may be out of adjustment. Check and adjust the vent valve each time the carburetor idle speed adjustment is made.
Adjust the idle only when the engine is at operating temperature and at the specified idle RPM. Once the idle speed is passed, the idle circuit is no longer in play. So, if you are trying to adjust the idle mixture and the idle is too high, you will get unpredictable results.
A rough idle could be caused by several things other than your Autolite 1100. For example valves bad, or weak, ignition, plugs points, or distributor. Don’t be too quick to blame your carburetor.
Replace that troublesome hot air choke with this electric choke conversion kit.