Employee of an Auto Emission Inspection Station in Norwood Ohio, Talking to a Customer Whose Station Wagon Has Just Failed the Carbon Monoxide Emission Test. The Driver Was Told Possible Causes for Failure Could Include: (1) Dirty Air Filter, (2) Clogged Crankcase Ventilation Valve Or Other Improperly Maintained Emission Control Device, (3) a Partially Closed Or Stuck Choke, Or (4) an Incorrect Carburetor Adjustment.
Photographer: Eiler, Lyntha Scott. Original public domain image from Flickr