User Manual

OPERATING INSTRUCTIONS
#3620

IEC 1997  IEC 1997
ABOUT THIS TOOL
The Vacuum Gauge provides an easy and efficient
means of checking engine vacuum or testing fuel
pump operation.
NOTE: This gauge has been calibrated for use at
sea level. When using the gauge at alti-
tudes above sea level, you MUST correct
the gauge indication to its true value at sea
level by adding one in. Hg for each 1,000
feet above sea level.
For example: An indication of 19 in. Hg at 2,000
feet above sea level would be adjusted to 21 in. Hg
(true value at sea level).
CHECKING VACUUM
Checking Vacuum at Engine Idle
NOTE: Refer to your vehicle's service manual to
obtain the manufacturer's specifications
for vacuum.
1. MAKE SURE the ignition is off.
2. Locate a vacuum hose which is connected
directly to the intake manifold. Disconnect the
vacuum hose and connect the gauge in its place.
3. Start engine and idle.
4. Note the value of vacuum and compare this
value to the manufacturer's specifications.
If vacuum indication is LOWER than specified,
check for the following:
■ Incorrect ignition timing
■ Incorrect valve timing or adjustment
■ Incorrect idle mixture screw adjustment
■ Worn piston rings (cylinder compression)
■ Intake manifold vacuum leaks
TO INTAKE
MANIFOLD
VACUUM HOSE
IEC