Equus 3620 User Manual

OPERATING INSTRUCTIONS

#3620

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 alti­tudes 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.

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IEC 1997

VACUUM HOSE

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

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IEC 1997

IEC

TO INTAKE
MANIFOLD

If vacuum indication OSCILLATES SLOWLY,
check for incorrect idle mixture screw adjust­ment.

If vacuum indication OSCILLATES RAPIDLY,
check for the following:

■ Sticky valve guides

■ Burned valve seats

■ Leak(s) in the head gasket

Checking Vacuum at High Speed

1. With gauge connected and engine idling as

described above, increase engine speed to
approximately 2000 RPM.

2. Note the new vacuum value.
If vacuum value at high speed is LOWER than

value at idle, check for restriction(s) in the
exhaust system.

If vacuum indication OSCILLATES, check for
weak valve springs.

3. Turn off the ignition. Remove the gauge and
RECONNECT THE VACUUM HOSE TO THE
INTAKE MANIFOLD.

CHECKING FUEL PUMP OPERATION

■ Carbureted vehicles only

WARNING: Please be aware that fuel systems are

HIGHLY FLAMMABLE. DO NOT
SMOKE WHILE PERFORMING THIS
TEST. Refer to safety precautions in

your vehicle's service manual. Follow
ALL required safety precautions to
prevent accidents, personal injury
and/or damage to your vehicle.

NOTE: Refer to your vehicle's service manual to

obtain the manufacturer's specifications
for fuel pump pressure.

1. Locate your vehicle's fuel pump. Disconnect the
hose between the fuel pump and the carburetor
and connect the gauge between the fuel pump
and the carburetor. Use clamps on fuel line
connections to avoid fuel leaks.

2. Turn the ignition on. Start and idle the engine.

3. Observe the gauge dialface for approximately

15 seconds. Note the fuel pump pressure and
compare this value to the manufacturer's
specifications.

If fuel pump pressure is LOWER than specified,
check for the following:

■ Restriction(s) in the fuel line

■ Defective fuel pump

If fuel pump pressure drops to LESS THAN
HALF ITS MAXIMUM VALUE in 15 seconds,

the fuel pump valves are leaking; replace the
fuel pump.

4. Turn off the ignition. Remove the gauge and

RECONNECT THE FUEL HOSE TO THE
FUEL PUMP.

WARRANTY AND SERVICE

The Manufacturer warrants to the original purchaser that
this unit is free of defects in materials and workmanship
under normal use and maintenance for a period of one (1)
year from the date of original purchase. If the unit fails
within the one (1) year period, it will be repaired or
replaced, at the Manufacturer's option, at no charge,
when returned prepaid to the Service Center with Proof of
Purchase. Installation labor is not covered under this
warranty. The sales receipt may be used for this purpose.
This warranty does not apply to damage caused by
improper installation, accident, abuse, improper voltage,
fire, flood, lightning, or other acts of God, or if the product
was altered or repaired by anyone other than the
Manufacturer's Service Center. The Manufacturer, under
no circumstances shall be liable for any consequential
damages for breach of any written warranty of this unit.
This warranty gives you specific legal rights, and you may
also have rights which vary from state to state. THIS
WARRANTY IS NOT TRANSFERABLE. For service,
send (prepaid) via U.P.S. (if possible) to manufacturer.
Allow 3-4 weeks service time. If you have any questions,
please contact your local store, distributor or the
Manufacturer's Service Center. USA & Canada: (800)
544-4124; All others: [phone] (9:00-4:00, Monday­Friday PST); FAX: [phone] (24 hr.)

TO

FUEL PUMP

FUEL HOSE

IEC

TO

CARBURETOR