zerokelvin

Just finished building up a 1985 22r truck. I passed everything on the smog except the RPM idle speed. Mine registered 1200 and the tech told me it's supposed to be 750 with a max of 950. I checked all the treads on here and tried everything I read. The idle adjustment screw does nothing... even when it's screwed all the way in, it doesn't even touch the trottle lever deal. I looked at a diagram and found a picture of the "fast idle cam" and it looks like there is a slot in it where the throttle lever "could" fit into and I think that would lower the idle, however it's not in the right position. I used a pick tool and found that it seems to be spring loaded (light) and does move. My questions are: is there a way to adjust the fast idle cam into a position where the trottle lever will fit into there and does this reduce the idle RPMs? Why does my idle adjustment screw do nothing? Again, I have read all the posts... sprayed around the carb, checked all the hoses, etc. There are no vacuum leaks, etc. Thanks for any help you provide.

Pepper

slow-mo

First, are you adjusting the correct screw?

On the Aisan carb, there are three adjustment screws and four if you have air conditioning.

Which screw are you adjusting?






Second, on my carburetor, the throttle valve will remain open ever-so-slightly. When the engine is idling, let's say at 1,000 rpms, I can close the throttle valve by hand just a little bit more. Then the idle will dropped down to 800 or so rpms. You may have a similar issue. With my carburetor it is not serious enough to investigate further. I can blip the throttle and sometimes that will bring down the rpms.




The Fast Idle Cam engages during cold engine starts. It will rotate into position via that spring you saw as well as indirectly via the choke lever. Once in position, the stepped cam will physically hold the throttle valve open at a higher rpm to accelerate (no pun intended) engine warm-up.

Once the engine coolant temperature reaches the correct level. the Choke Opener will forcibly remove the Fast Idle Cam and whatever is left of the choke itself.

zerokelvin

So I was adjusting the "idle speed screw" on mine, according to your pic. I did not see the fast idle screw down at the bottom on mine... was doing this at night (dumb). will adjusting the fast idle screw lower the rpms? Mine is idling warm at 1200 and it needs to be below 950. Also, the part that I thought was the fast idle cam must be something else. It is also not in the picture you provided. I think I might have a different or newer version of the oem carb. Thanks for your long post, has given me a few more outs.

Pepper