drsantos,
Your 81 has an electric choke. First check to see that the wire is plugged onto the choke element(sometimes they just fall off), with the engine running ther should be 12 volts at that connection, if there is not, check the fuse. If that is ok then check the oil pressure sending unit, I believe that the 12 volt source on an 81 comes through the engine oil pressure sender. It can actually come from any 12 volt source that turns off with the key if you need to rewire it. If you have 12 volts, remove the air cleaner so that you can verify that the choke opens, if it does not then you need to replace the choke element as it has likely broken. If the choke does open, but the idle still won't kick down then you have a linkage problem that is causing a bind and not allowing the latch to drop out. Look close and you should be able to see the culprit. Hope this helps to solve your problem.
