Idle Adjustment Screw Has Only 1/4 turn adjustment

[Randy_L]

The engine (1981) is newly rebuilt (but not the CIS). Tried to adjust the idle speed and found that the idle screw turns easily but only one quarter of a turn in either direction, then comes to a dead stop. What would cause that? The setup looks very simple — just a tube cast onto the side of the throttle body.

[icarp]

we need much more info on the type of fuel delivery system you have
pics would help as well
Ian

[jbs3]

Check the smoothness of the outside of the screw head. I just had my idle screw out of the throttle body and discovered that someone had taken a very aggressive approach to adjusting it. There were deep teeth marks from some type of tool on the exterior of the screw head which had managed to get caught into the top of the spring and stop it from turning. I had to file them down to let the screw turn freely. This is a pic after the cleaning up.

[Randy_L]

icarp — CIS, 1981 version.

jbs3 — Thanks, man. I'll check it out. From the photo you posted, just doesn't look like there's anything else that could cause the problem... unless there was something inside the tube blocking it, but that doesn't seem likely at all. I'll be surprised if you haven't solved the issue.