My 72 RT360 hunts around for an idle which I understand may indicate a lean running condition. Also, when warmed up it can randomly rev uncontrollably when I blip the throttle.  I mean it just revs to the maximum and stays there until I un screw the idle mixture screw a little and it shuts off. I did not think the cable was sticking, the throttle appears to close at the grip. Where might I have a problem both with lean running? (Should I increase the main jet size or move the needle settings?) And what is up with all those revs? I live at sea level in case that makes a difference re the jetting. 

If throttle is closing reliably...  should "clunk" closed...  then it's most likely an air leak. 

Slide sticking up when you give it a handful of throttle. Loosen the flange nuts say two flats & try it again, then go three flats if still does it. Those old carbs pull the slide body out of shape when tightening the flange nuts. If that helps the sticking then we'll think of what to do next. Better still, if there's room, pull the cable at the carb up & down, see if slide feels free. Get it back into the adjuster though or she'll rev for sure.

In addition to the carb sticking as previously mentioned check the cylinder bolts and nuts. The 360 has 8. 4 small nuts that secure the head to the cylinder and 4 large bolts that secure the cylinder and head assembly to the crankcase. If the 4 large ones get loose the 4 small ones will be able to maintain compression if they are tight. When the 4 large ones loosen then the cylinder will raise up and allow air to leak in at the base. If the base gasket is aftermarket it might be too thick. It will allow the bolts to loosen when the engine expands and contracts as it heats up and cools down. This happened to me on an RT3 that was restored before I bought it. It had an aftermaket base gasket that was twice as thick as OEM. Suggest using OEM base gaskets only.

The crankshaft seals can also leak.

Also if it happens on a 250 the engine won't run as it won't maintain compression with only 4 bolts.

The head on my 71 dt1e only has 4 bolts holding it down