Dashpot: Testing and Inspection

Fig. 20 Dash Pot To Vacuum Transmitter Valve Hose:

Fig. 24 Dash Pot Setting Speed Adjustment:

1. Start engine and warm-up to normal operating temperature.
2. Check that idle speed is 700 rpm.
3. Maintain engine speed at 3,000 rpm with the throttle valve. Pinch the vacuum hose between the dash pot and the vacuum transmitting valve (VTV). Fig. 20
4. Release the throttle valve and check the DP setting speed.

DP Setting Speed: 2,000 rpm


5. If not as specified, adjust using the DP adjusting screw. Fig. 24
6. Check the operation of the VTV by racing the engine to 3,000 rpm and pinching the vacuum hose, as in step 3.
7. Release the pinched hose. The engine should return to idle speed in approximately 1 second.
8. If operation is not as specified, remove and inspect VTV.
9. Remove the filter element from the cap on the black end of the VTV. Check the VTV air filter for contamination or damage.
10. Using compressed air, clean the VTV filter.

Fig. 27 Testing Vacuum Transmitting Valve:

11. Check the VTV by blowing air through each side of valve, Fig. 27. Air should flow without resistance from B to A. Air should flow very little from A to B.
12. If a problem is found, replace the VTV.
13. Reinstall the VTV on engine and recheck DP operation.