Yup, timing advanced.
Setting the timing is easy, but different for vacuum advance and centrifugal advance. Go out and get a good VW shop manual like Bentleys or Haynes, just to read their timing set explanation.
But for us "real men" who don't read manuals (yeah, right....) here we go:
BTW: there are a number of questions to answer before diving into this, like what type of disti you have (vacuum, Bosch 009, etc) but this explanation is generic (mainly included because there is nothing in the knowlege section on how to time your engine!!!
Vacuum advance: (It'll have a vacuum hose running from the carb(s) or intake manifold to a little diaphragm on the side of the distributor): Pull off the vacuum line at the disti and plug it (gently) with a pencil. Loosen the clamp at the base of the disti to allow movement with a little effort (not super-loose). Buy or borrow a 12 volt timing light, and attach it to power and #1 cylinder spark plug wire as per the lights' instructions.
The timing mark (notch) is on the crankshaft pulley at top dead center (TDC) and may or may not have an indicator just to the side of the center of the case, (the case center is where the two sides of the case come together). The indicator has little notches in it noting 2,4,6,etc degrees of advance (this is also assuming you have a pulley with no timing degrees on a sticker on the face of the pulley). Alternatively, sometimes there is no indicator, but the stock pulley has one big and one small notch on the pulley lip.
OK, to time this disti, make sure the timing light is hooked up and the lights' wires are away from moving pulleys, and give you room to move around the disti. Start the engine, and, when you pull the trigger on the light you should see it pulse (DON'T look directly at it!!) - aim it at the crankshaft pulley (this is best done in a garage away from the Sun) and you should see the timing notch sitting somewhere near the top, adjacent to a notch on the indicator (dual-notch pulleys explained later). Note where it is in degrees on the indicator, and back it down a couple of degrees by turning the body of the disti clockwise or anti-clockwise (as you turn the body, you'll see the timing mark move against the scale). The VW manuals show different timing specs for different years and they're all over the place. I like to start with 6 degrees advanced and work from there. Pretty cool, huh? And you thought it might be complicated!......If you have a dual-notch pulley, line the smaller notch up on the case half division, and that's it.
Once you get it where you want it, stop the engine and tighten the clamp on the bottom of the disti shaft (not too tight, and don't move the body!), re-connect the vacuum hose, remove the timing light and re-connect the #1 spark plug lead, then take it out for a test. See if it now stops better when you shut it off. If not, try backing the advance down another degree (but no lower than 4 degrees). If that doesn't cure it, let us know and we'll go from there (may be overheated fuel lines or something else).