System Testing
- Remove air cleaner cover, then start engine and allow to idle. Place finger over air inlet tube and check for vacuum. There should be no vacuum. If there is no vacuum, proceed to next step. If vacuum is felt, replace anti-afterburn valve and repeat test.
- Quickly raise engine speed to 3500 RPM and close throttle quickly. Again check for vacuum at inlet. If vacuum is felt, valve is okay. If vacuum is not felt, locate restriction or blockage and retest. If vacuum is still not felt, replace anti-afterburn valve and retest.