1977 Models
- Disconnect vacuum hose from throttle control diaphragm. Connect vacuum gauge to hose. Vacuum should be at least 1.2 in. Hg at 4000 RPM.
- On Federal models, if there is vacuum, replace dashpot check valve and repeat THROTTLE OPENER SYSTEM test. On California and high altitude models, if there is vacuum, by-pass throttle control valve and repeat THROTTLE OPENER SYSTEM test.
- If throttle return time is within specification, replace throttle control valve. If throttle return time is still less than one second, check for vacuum at dashpot.
- If vacuum is available, replace dashpot check valve. If no vacuum, check hoses for leaks. Remove throttle control by-pass and repeat THROTTLE OPENER SYSTEM test.
- On all models, if no vacuum is available, check for vacuum at carburetor vacuum port. If vacuum is available at carburetor vacuum port, check hoses for leaks or blockage. Repeat THROTTLE OPENER SYSTEM test. If there is no vacuum at carburetor, clean port and repeat THROTTLE OPENER SYSTEM test.