TM 9-8000
(45.05 km/h), and then stopped and idled for E minutes.
tube whose bottom end is dipped in mercury. The
The vehicle then was moved out again accelerated to
reading then is obtained by measuring how far in inches
approximately 45 mph (72., km/h) and did stop-and-go
the mercury rises In the tube. A vacuum gage Is very
driving for about 3: minutes, accelerating from 0 to 45
useful for:
mph (72., km/h) three times and traveling about 15 miles
a. Engine Diagnosis. A vacuum gage can locate
(24.13 km). At 8:11 am it stopped, after having traveled
approximately 15 miles (24.13 km). I idled for about 48
things such as valve malfunctions, manifold vacuum
minutes and then was shut down at 9 am.
leaks, or improperly adjusted ignition timing.
b. Driving for Maximum Efficiency. Because intake
17-8. Vacuum Gage (Fig. 17-22). A
vacuum gage
manifold vacuum decreases proportionally with engine
measures the difference in pressure between the Intake
load increases, the vacuum gage can be used as a
manifold and the atmosphere in Inches of mercury
driving aid to attain maximum fuel economy and engine
(InHg). The unit of measure Is derived from applying a
life.
vacuum to the top end of a
17-16