My 73 has a problem with starting after a short run.  I went out last night on an errand in prep for a drive this weekend and made a stop after a 3 mile drive.  Came back to the car and it was real hesitant to run.  It would start but not stay running.  After several attempts (~6) the car fired up but ran rough for a minute then took off with no problems.  This has happened once before.  Has the Qjet carb with standard ignition.  Gas is new.   Point me in the right direction, right now I see lots of possibilities.

Sounds like the fuel may be boiling over in the carb, or maybe the float level is too high. It could be that the float has soaked up enough fuel to be too heavy.
Another possibility is the plugs in the bottom of the bowl are leaking, a REAL common problem on Quads. Once it sits for a while, it drains all the fuel out of the fuel bowl into the intake, causing hard starts, and rough running until the fuel is all burned/cleared out.