1975 Models

Disconnect hoses between carburetor-to-altitude compensator and evaporation compensator valve-to-altitude compensator valve at altitude compensator valve. Start and run engine at idle. With fingers, close both sides of altitude compensator valve. See Fig 1. If altitude compensator valve is working properly, engine speed will drop.

Fig 1: Altitude Compensator Valve Test

Courtesy of MAZDA MOTORS CORP.