Vacuum Advance Bearing Mechanism.
Common problem, it's a little piece of plastic that holds some ball bearings for the innards of the dizzy to rotate on when the vacuum pulls on the mechanism. It also has a spring which allows the mechanism to return to base point.
As the car ages, the little plastic thing gets brittle and eventually breaks and sheds little ball bearings all over the inside of the dizzy. Common problems are hiccupping, poor idle, back-firing through the carbs, even real lousy acceleration.
The part is available through Nissan, would have to look up the part number, but that's usually all it needs. If I recall right , they're only about $20.00 or so.
But why sell the car?
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