Ensure all point gaps are properly set. Warm engine to normal operating temperature and connect tachometer to engine. Connect timing light to leading (lower) spark plug on front rotor housing.
Start and run engine at idle speed. Check leading timing. If not to specifications, adjust timing by rotating distributor housing until correct. Tighten lock nut and recheck leading timing.
Connect timing light to trailing (top) spark plug on front housing. Start engine and check trailing timing. See Fig 1. Use external adjusting lever, loosen vacuum unit attaching screws, or loosen leading side breaker base assembly to adjust trailing timing. See Figure.

Fig 1: Typical Ignition Timing Marks
Courtesy of MAZDA MOTORS CORP.

1977 IGNITION TIMING SPECIFICATIONS

1978-79 IGNITION TIMING SPECIFICATIONS

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

• You smell fuel, burning insulation, or see smoke.

• Brakes feel soft, pull hard to one side, or make grinding noises.

• The engine overheats, stalls repeatedly, or misfires under load.

• You are missing required tools, torque specs, or safe lifting equipment.

• You are not confident in the next step or safety outcome.

Safety Warning

1977-79 Models