Volkswagen Repair: 71 Convertible VW bug, distributor shaft, primary coil

Question
Just had a new carb installed because the car was starting and then wouldn't stay running. Drove it a few times it was great and now it will start but it will not keep running at all...any ideas? I have checked the entire fuel system....

Answer
Hi Cindy;
To maintain operation the engine needs both fuel, and ignition.  If you've thoroughly checked the fuel system, then maybe the ignition system needs a little tweaking.  It is possible for the points in the distributor to get too close to one another, and that will make the engine stop running.  If they stay close together, that will keep it from running too.  But, I would check to see that the points are gapped correctly.  The thickness of a cardboard matchbook cover is "just right."  Take the distributor cap off, turn the engine over, until the little bump on the distributor shaft, is at the points "follower."  Theres' a little "foot" that sticks out of the point set that rubs against the distributor shaft, and when it gets to the bump on the shaft it opens up the points, and as the distributor shaft turns, and "AC waveform" is generated which allows the electrical energy in the primary coil winding to rise, and fall, and as this happens there is an "induced" current flow in the secondary winding of the ignition coil that generates a large voltage of low current that turns out to be the spark voltage at the spark plug.  Anyway, if the little foot is at the bump, and the points are still closer together than the thickness of that matchbook cover, there isn't enough "GAP," and the spark voltage will be too low to fire the fuel in the engine...hence the engine dies, and until it cools off enough it won't run.  Once it gets cool, the choke closes, the mixture gets richer, and the molecules get closer together, and there may be just enough spark energy to make the car run until it gets too hot again, and then it quits.  Anyway, there is a screw that holds the points apart at this place, and its on the base of the distributor.  Loosen the screw, set the "gap," and then tighten the screw.  That should get the car up, and running again.  I know a matchbook works because I carried one around for just such an occasion.  The screw in the distributor just loosens up due vibration, and such.  Don't try to overtighten it, just make it good and snug.  Otherwise you'll strip it out, and need a whole new distributor.  I hope this get's you, and your "BUG" up and running again.  Good luck, Cindy.