91 B2200 Poor idle during warm-up
 

Hey Everybody,

I have a 1991 B2200 that's doing something strange I was hoping I could get some ideas on. When I start it in the morning, it starts up and as long as I don't hit the gas or anything it starts at about 2-2.5k RPMs. Over the next few minutes, if left alone, it starts to creep up slowly to over 5k+ RPMs. If I hit the gas it immediately drops the idle really low and often dies. It idles really bad (if at all) until the truck is warmed up then it runs good with no problems after fully warmed up. Anybody experience this? Any thoughts? I'm not even sure if they made any with fuel injection but my truck is Carb. Thanks in advance!

You need to check

if the accelerator cable is binding or carb throttle binding, try to "release" by hand

if the throttle return spring is closing the throttle completely when you release the accelerator (a real issue if your carb has been changed to a Weber carb, as the supplied spring in the kit is WAY too weak)

make sure that the wire to the carb electric choke is plugged into the rear of the alternator; if not, the carb butterfly will remain "closed", causing a rich mixture and high idle (just happened on mine, I knocked that wire out of the alternator while replacing a belt)