Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
High Altitude Compensation System: Operation
Solenoid valve opens a passage between air cleaner and carburetor. Fresh air will then pass through 3 main metering orifices and be supplied to idle and off idle systems in addition to primary and secondary main metering systems. The high altitude idle-up solenoid valve will open a passage to a port located downstream of throttle valve. Additional air/fuel mixture will be supplied to engine, permitting stable idle RPM at high altitude. See Fig 1 .
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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.