Why does your 1973 super beetle knock when you shut it off?

Answer 1

Because your timing's too retarded. You're probably running REAL hot too.

You can time your engine one of two ways, and you need a timing light for either--the "static" timing light John Muir talks about is no good for a 1600 engine. If you've got the stock pulley you'll find a notch in it. It aligns with the seam in the case--they put in the offset you need because the correct timing is 5 degrees BTDC. If you've got a degree wheel, you want the 0 line to be to the left of the seam.

Once you've done that, reach up to the throttle lever on the carb and jerk it toward you. No I'm not kidding--grab it and give it a hard yank. If the engine has a lag between you yanking and it accelerating, you need to tweak the timing a little.