Nissan Repair: Here is the ?, air fuel mixture, heather heather

Question
HOWDY MR SUDDERTH I HAVE A 87 NISSAN SENTRA I HAVE REBUILT THE CARB BUT IT SEEMS TO STILL NOT BE RUNNING PROPERLY I HAVE SEARCH THE WEB OVER AND OVER AND CANT SEEM TO GET THE ANSWER I AM LOOKING FOR I CAME ACROSS YOU AND I AM HOPING YOU CAN TELL ME WHERE THE IDLING SCREW IS AT ON THE CARBURATOR.  YEA ITS SILLY BUT I HAVE BEEN WORKING ON CARS FOR A WHILE AND THIS ONE HAS GOT ME.  THERE ARE MANY SCREWS AROUND BUT I WHAT TO MAKE SURE I HIT THE RIGHT ONE. THANKS  HEATHER

Answer
Heather,

There are a couple of screws on this carburetor.  My bet is it does not need adjustment, unless someone has screwed with it before.  The problem with these carburetor is the power vavle.  Looks like a brass tube with a couple of wires.  These fail and stick open and flood the engine where is idle like crap and gets horrible gas mileage.  I have simply replaced the power valve on so many I cannot remember.  But, for your question, the idle stop screw, there are several.  Once the car is at operating temperature there is a normal stop screw on the side that the linkage attaches to.  Look at the throttle arm as you actuate it and see how it stops.  On the other side there is the fast idle speed screw.  If has not been touched leave it alone.  The air fuel mixture screws should be blocked.  If they have been exposed turn in all the way and then counter-clockwise one and a half turns out as a baseline.  Once the car warms up turn the screw out until the car stumbles and then in until it stumbles and then center the screw between these two points.  Need more please email me.