Page 1
140 PSI TWIN CYLINDER
AIR COMPRESSOR PUMP
FOR 3 HP MOTOR
Model
93785
SET UP AND OPERATING INSTRUCTIONS
Visit our website at: http://www.harborfreight.com
Read this material before using this product.
Failure to do so can result in serious injury.
SAVE THIS MANUAL.
Copyright© 2009 by Harbor Freight Tools®. All rights reserved. No portion of this manual or any artwork
contained herein may be reproduced in any shape or form without the express written consent of
Harbor Freight Tools. Diagrams within this manual may not be drawn proportionally. Due to continuing
improvements, actual product may differ slightly from the product described herein. Tools required for
assembly and service may not be included.
For technical questions or replacement parts, please call 1-800-444-3353.
Manual Revised 09j, 09k
Page 2
CONTENTS
ASSEMBLY DIAGRAM ................ 18
IMPORTANT SAFETY
INFORMATION ............................ 3
GENERAL SAFETY WARNINGS .......3
COMPRESSOR PUMP SAFETY
WARNINGS ......................................4
AIR COMPRESSOR SAFETY
WARNINGS ......................................5
GROUNDING (FOR MOTOR) ........ 7
SYMBOLOGY .....................................7
SPECIFICATIONS .......................... 8
UNPACKING .................................. 8
INSTRUCTIONS FOR PUTTING
INTO USE .................................... 8
FUNCTIONS ....................................... 8
COMPRESSOR AREA SET UP ......... 8
LIMITED 90 DAY WARRANTY .... 19
INSTALLATION. ................................9
CHECKING THE OIL ........................ 10
GENERAL OPERATING
INSTRUCTIONS ........................ 11
EMERGENCY
DEPRESSURIZATION ...................12
MAINTENANCE AND
SERVICING ............................... 13
CLEANING, MAINTENANCE, AND
LUBRICATION ...............................13
MAINTENANCE SCHEDULE ........... 13
OIL MAINTENANCE ......................... 14
DRAINING MOISTURE FROM THE
TANK .............................................. 14
AIR FILTER MAINTENANCE ........... 14
TROUBLESHOOTING ...................... 15
PARTS LIST ................................. 17
Page 2For technical questions, please call 1-800-444-3353.SKU 93785
Page 3
SAVE THIS MANUAL
Keep this manual for the safety
warnings and precautions, assembly,
operating, inspection, maintenance and
cleaning procedures. Write the product’s
serial number in the back of the manual
near the assembly diagram (or month
and year of purchase if product has no
number). Keep this manual and the
receipt in a safe and dry place for future
reference.
not avoided, could result in
minor or moderate injury.
NOTICE is used to
address practices
not related to personal injury.
CAUTION, without
the safety alert
symbol, is used to address
practices not related to
personal injury.
General Safety Warnings
IMPORTANT SAFETY
INFORMATION
In this manual, on the labeling,
and all other information
provided with this product:
This is the safety alert
symbol. It is used to alert
you to potential personal
injury hazards. Obey all
safety messages that
follow this symbol to avoid
possible injury or death.
DANGER indicates
a hazardous
situation which, if not
avoided, will result in death or
serious injury.
WARNING
indicates a
hazardous situation which, if
not avoided, could result in
death or serious injury.
CAUTION, used
with the safety
alert symbol, indicates a
hazardous situation which, if
WARNING Read all safety
warnings and instructions.
Failure to follow the warnings and
instructions may result in electric
shock, re and/or serious injury.
Save all warnings and
instructions for future reference.
Work area safety1.
Keep work area clean and well a.
lit. Cluttered or dark areas invite
accidents.
Do not operate the Compressor b.
Pump in explosive atmospheres,
such as in the presence of
ammable liquids, gases or dust.
Compressor motors produce sparks
which may ignite the dust or fumes.
Keep children and bystanders c.
away from an operating
compressor pump.
Personal safety2.
Stay alert, watch what you are a.
doing and use common sense
when operating this compressor
pump. Do not use this compressor
pump while you are tired or under
the inuence of drugs, alcohol or
medication. A moment of inattention
REV 09j
Page 3For technical questions, please call 1-800-444-3353.SKU 93785
Page 4
while operating a compressor pump
may result in serious personal injury.
Use personal protective b.
equipment. Always wear eye
protection. Safety equipment such
as a dust mask, non-skid safety
shoes, hard hat, or hearing protection
used for appropriate conditions will
reduce personal injuries.
Only use safety equipment c.
that has been approved by an
appropriate standards agency.
Unapproved safety equipment may
not provide adequate protection. Eye
protection must be ANSI-approved
and breathing protection must be
NIOSH-approved for the specic
hazards in the work area.
Compressor Pump use and care3.
Do not use the unit if its power a.
switch does not turn it on and off.
Any tool that cannot be controlled
with its power switch is dangerous
and must be repaired.
Disconnect the plug from the b.
power source before making
any adjustments, changing
accessories, or storing the
compressor pump. Such preventive
safety measures reduce the risk of
starting the unit accidentally.
Store an idle compressor pump c.
out of the reach of children and
do not allow persons unfamiliar
with the compressor pump or
these instructions to operate it. A
compressor pump is dangerous in the
hands of untrained users.
Maintain the compressor pump. d.
Keep the compressor pump clean
for better and safer performance.
Follow instructions for lubricating
and changing accessories. Keep
the outside surfaces dry, clean and
free from oil and grease. Check for
misalignment or binding of moving
parts, breakage of parts and any
other condition that may affect the
compressor pump’s operation. If
damaged, have the compressor
pump repaired before use. Many
accidents are caused by a poorly
maintained compressor pump.
Use the compressor pump e.
in accordance with these
instructions, taking into account
the working conditions and the
work to be performed. Use of the
compressor pump for operations
different from those intended could
result in a hazardous situation.
Service4.
Have your compressor pump a.
serviced by a qualied repair
person using only identical
replacement parts. This will ensure
that the safety of the compressor
pump is maintained.
Compressor Pump
Safety Warnings
Wear ANSI-approved safety goggles 1.
during use.
Install pulley and belt safety guard 2.
before use.
Before rst and every use, verify 3.
Pump has sufcient oil.
The use of accessories or 4.
attachments not recommended by
the manufacturer may result in a risk
of injury to persons.
REV 09j
Page 4For technical questions, please call 1-800-444-3353.SKU 93785
Page 5
Misalignment between Motor 5.
and Pump can damage the Belt
Wheel. Use a straight edge, such
as a yardstick, to check and adjust
alignment as needed.
Use proper size motor and motor 6.
pulley. This air compressor Pump
must be installed with a 3 HP electric
motor and pulley (both not supplied)
which can turn the Air Compressor
Belt Wheel at approximately 1050
rpm, but not more than 1200 rpm.
Install motor, pulley belt and pulley 7.
belt cover securely. Be sure to use
the proper size bolts to install your
motor (not included). The belt and
belt cover (not included) must be
strong enough to prevent breaking
and possible injury.
Be sure all equipment is rated to 8.
the appropriate capacity of this
pump. Make sure that the lowest
rated piece of equipment you are
using can handle the maximum
pressure of the Air Compressor Pump
(see Specications).
Do not direct the air outlet at any 9.
person or animal.
Use Safety Guard for Pulleys.10. The
Air Compressor Belt Wheel (35),
V-belt (not supplied), and motor
pulley (not supplied) must be covered
by a safety guard (not supplied)
covering all moving elements before
operation.
Avoid burns. 11. The Cylinder (12),
Cylinder Head (5) and Air Outlet (6)
become very hot during operation. Do
not touch.
Air Compressor Safety Warnings
Risk of re or explosion - Do not 1.
spray ammable liquid in a conned
area or towards a hot surface. Spray
area must be well-ventilated. Do not
smoke while spraying or spray where
spark or ame is present. Arcing
parts - Keep compressor at least 20
feet away from explosive vapors,
such as when spraying with a spray
gun.
Risk of bursting - Do not adjust 2.
regulator higher than stated
maximum pressure of attachment.
Risk of injury - Do not direct air 3.
stream at people or animals.
To reduce the risk of electric shock, 4.
do not expose to rain. Store indoors.
Wear ANSI-approved safety goggles 5.
during use.
Do not use to supply breathing air. 6.
Drain Tank daily and after use. 7.
Internal rust causes tank failure and
explosion.
Add correct amount of compressor 8.
oil before rst use and every use.
Operating with low or no oil causes
permanent damage and voids
warranty.
Do not remove the valve cover or 9.
adjust internal components.
Do not use the air hose to move the 10.
compressor.
Release the pressure in the storage 11.
tank before moving.
The use of accessories or 12.
attachments not recommended by
REV 09j
Page 5For technical questions, please call 1-800-444-3353.SKU 93785
Page 6
the manufacturer may result in a risk
of injury to persons.
All air line components, including 13.
hoses, pipe, connectors, lters, etc.,
must be rated for a minimum working
pressure of 150% of the maximum
system pressure.
USE OF AN EXTENSION CORD 14.
IS NOT RECOMMENDED. If you
choose to use an extension cord, use
the following guidelines:
RECOMMENDED MINIMUM WIRE
GAUGE FOR EXTENSION CORDS
(120 VOLT)
NAMEPLATE
AMPERES
(at full load)
0 – 6 18 16 16 14
6.1 – 10 18 16 Do not use.
10.1 – 12 16 16 Do not use.
12.1 – 16 14 12 Do not use.
EXTENSION CORD
LENGTH
25’ 50’ 100’ 150’
TABLE A
Make sure your extension cord is in a.
good condition.
Be sure to use an extension cord b.
which is heavy enough to carry the
current your product will draw. An
undersized cord will cause a drop in
line voltage resulting in loss of power
and overheating. Table A shows
the correct size to use depending
on cord length and nameplate
ampere rating. If in doubt, use the
next heavier gauge. The smaller the
gauge number, the heavier the cord.
Industrial applications must follow 15.
OSHA guidelines.
Maintain labels and nameplates 16.
on the compressor. These carry
important safety information. If
REV 09j
unreadable or missing, contact
Harbor Freight Tools for a
replacement.
This product is not a toy. Keep it out 17.
of reach of children.
Operate unit on level surface. Check 18.
oil level daily and ll to marked level if
needed.
People with pacemakers should 19.
consult their physician(s) before
use. Electromagnetic elds in close
proximity to heart pacemaker could
cause pacemaker interference or
pacemaker failure.
WARNING: The brass components 20.
of this product contain lead, a
chemical known to the State of
California to cause birth defects (or
other reproductive harm). (California
Health & Safety code § 25249.5, et
seq.)
By supplying this air compressor 21.
pump, Harbor Freight Tools makes
no representations and accepts no
responsibility for the motor, V-belt,
enclosure or mounting surface not
supplied by HFT which may be
used in the installation. You are
strongly advised to have this pump
properly installed by a qualied
service technician using appropriate
components in good condition.
The warnings, precautions, 22.
and instructions discussed in
this instruction manual cannot
cover all possible conditions and
situations that may occur. It must
be understood by the operator that
common sense and caution are
factors which cannot be built into this
Page 6For technical questions, please call 1-800-444-3353.SKU 93785
Page 7
product, but must be supplied by the
operator.
SAVE THESE
INSTRUCTIONS.
GROUNDING (FOR MOTOR)
TO PREVENT
ELECTRIC SHOCK
AND DEATH FROM
INCORRECT GROUNDING
WIRE CONNECTION:
Check with a qualied
electrician if you are in doubt
as to whether the outlet is
properly grounded. Do not
modify the power cord plug
provided with the motor.
Never remove the grounding
prong from the plug. Do not
use the motor if the power
cord or plug is damaged. If
damaged, have it repaired by
a service facility before use. If
the plug will not t the outlet,
have a proper outlet installed
by a qualied electrician.
V~
A
n0 xxxx/min.
Symbology
Double Insulated
Canadian Standards Association
Underwriters Laboratories, Inc.
Volts Alternating Current
Amperes
No Load Revolutions per Minute
(RPM)
REV 09j
Page 7For technical questions, please call 1-800-444-3353.SKU 93785
Page 8
SPECIFICATIONS
Compressor Type
Maximum Air
Pressure
Maximum Speed 1200 RPM
Air Delivery
(@ 1050 RPM)
Oil Type
Flywheel
Belt Type A or 4L
Mounting Hole Pattern 5-3/4” x 5”
Overall Dimensions
Single Stage Twin
Cylinder
140 PSI
10 SCFM @ 40 PSI
8 SCFM @ 90 PSI
7.4 SCFM @ 115 PSI
SAE 30W non-detergent
Air Compressor Oil
(Sold separately)
(SKU 95048)
10-1/4” dia. x 1-7/64”
wide, V-groove
12-1/4”H x 6-3/4” W x
11-3/4”D
any adjustments to the motor,
tank, and/or compressor
pump.
Note: For additional information regarding
the parts listed in the following pages,
refer to the Assembly Diagram near
the end of this manual.
Functions
Cylinder
Head
(5)
Oil Breather
Plug (15)
Air Filter (4)
Flywheel
(35)
UNPACKING
When unpacking, make sure that the
item is intact and undamaged. If any parts
are missing or broken, please call Harbor
Freight Tools at 1-800-444-3353 as soon
as possible.
INSTRUCTIONS FOR
PUTTING INTO USE
Read the ENTIRE IMPORTANT
SAFETY INFORMATION
section at the beginning of this
manual including all text under
subheadings therein before set
up or use of this product.
TO PREVENT
SERIOUS INJURY
FROM ACCIDENTAL
OPERATION:
Turn off and unplug the motor
before assembling or making
REV 09j, 09k
Oil Fill
Screw
Oil Sight
Glass (22)
Crankcase (16)
(13)
Figure 1
Compressor Area Set Up
Designate a work area that is clean 1.
and well-lit. The work area must not
allow access by children or pets to
prevent injury.
Locate the Compressor Pump and 2.
attachments on a at level surface to
ensure proper pump lubrication and
to prevent damage to the unit. Keep
at least 12” of space around the unit
to allow air circulation.
Route the power cord from the motor 3.
to the grounded wall outlet, along a
safe path without creating a tripping
Page 8For technical questions, please call 1-800-444-3353.SKU 93785
Page 9
hazard or exposing the power cord to
possible damage.
Assembly
Make sure that the inner faces of 1.
the wheel socket as well as the
Crankshaft (29) are clean and free of
burrs and roughness.
Apply a thin layer of grease to the 2.
interior of the socket and, with the
ridge end of the beltway pointing
towards the compressor, slide the
Belt Wheel (35) over the Crankshaft.
CAUTION: Avoid damage to the Air
Compressor Pump and other
equipment. Make sure the mounting
surface on which the Air Compressor
Pump is installed is at, level and
strong enough to support the pump,
motor and tank.
Place the Air Compressor Pump on the 1.
mounting surface at the same level as
the 3 HP motor used to drive it.
Note: Use a motor with the appropriate
size pulley to get the Pump RPM.
Pump Pulley
WARNING! Do not force or hammer the
Belt Wheel onto the Crankshaft.
Washer
(34)
Figure 2
Bolt (32)
Wrench
(not included)
Belt Wheel (35)
3. Slide Washer (34) onto the Bolt
(32) and insert the Bolt through Belt
Wheel and thread into Crankshaft.
Tighten using Wrench (not included) See Figure 2.
Note: The Bolt is a left-hand thread. To
fasten, turn Bolt counterclockwise.
Installation.
Note: Depending on your level of
expertise, you may wish to have a
qualied technician perform this
installation.
Motor Pulley
10.25”
Pump Pulley Dia:
Calculation for Motor Pulley:
10.25’ 1050
(Pump Pulley Dia. x Pump RPM)
Motor RPM
x
=
To calculate the motor and motor
pulley needed to power the pump,
multiply the Pump diameter (10.25”)
times the pump working RPM (1050),
then divide by the engine RPM.
This will determine the motor pulley
diameter (in inches) needed to run
the unit.
For example: If you have a 1725
RPM motor, to calculate the pulley
diameter needed, multiply 10.25 x
1050, then divide by 1725, which
equals the motor pulley size of 6.24”.
Use the pulley size closest to this
gure.
Motor
Pulley
Dia.
REV 09j
Page 9For technical questions, please call 1-800-444-3353.SKU 93785
Page 10
10.25 x 1050
1725
6.24”
=
Or, use the following equation if you
have a 3450 RPM motor:
Mount the motor (not supplied) 10.
as recommended by the motor
manufacturer. Be sure that the motor
is securely mounted.
10.25 x 1050
3450
3.12”
=
2. The 10-1/4 inch V-groove Belt Wheel
(35) of the Air Compressor Pump
must be in perfect alignment with the
motor pulley (not included).
Note: Ensure the Belt Wheel is installed
for counter-clockwise rotation when
facing the Belt Wheel side of the
Pump.
CAUTION: Misalignment between Motor
and Pump can damage the Belt
Wheel. Use a straight edge, such
as a yardstick, to check and adjust
alignment as needed.
Verify that Belt Wheel turns freely 3.
where it overhangs mounting surface.
Place a V-groove belt (not included) 4.
over Belt Wheel (35) and motor pulley.
Pull Compressor Pump until properly 5.
aligned, and the belt is tight. Recheck
motor pulley, V-groove belt, and Belt
Wheel alignment.
Use a pencil to mark through the Air 6.
Compressor Pump mounting holes
onto the mounting surface.
Move Air Compressor Pump and drill 7.
four 3/8” holes in mounting surface.
Make nal alignment and adjust 11.
belt tension with the motor. It may
be necessary to loosen the motor
mounting bolts to adjust the motor
location. To test the proper tension
on the V-belts, press down on the
belts, they should not depress more
than 1/2 inch at mid span. Tighten all
mounting hardware.
Push down on Belt Wheel with your 12.
hand and tighten the Belt Wheel bolt.
Connect plumbing hardware (not 13.
supplied) from the male ¾”- 14 TPI
Air Outlet (6) to the air destination
(i.e., air pressure tank, not supplied),
routing the tubing in the shortest
possible path.
Install a safety guard (not supplied) 14.
that surrounds the Motor Pulley,
V-belts, and Belt Wheel. This safety
guard must cover all sides of the
moving belts and pulleys. It should
have a clearance of about one inch
from the moving parts. The safety
guard must be sturdy enough to
prevent injury.
Note: A qualied electrician must wire in
a pressure switch control that turns
off motor when the pump reaches the
desired pressure (140 PSI or less).
Move the Air Compressor Pump back 8.
to its mounting position.
Secure each corner of base with 9.
a 3/8” diameter bolt, washer, lock
washer, and nut (all not supplied).
REV 09j
Note: Always install Air Compressor Pump
to air tank that can withstand at least
140 PSI and has a safety valve.
Note: A high/low cut-in/cut-out switch
(not included) can be incorporated
to operate a motor starter or motor
Page 10For technical questions, please call 1-800-444-3353.SKU 93785
Page 11
contractor for semi-automatic control
of air pressure in the vessel.
WARNING! Avoid serious injuries. Do not
operate this Air Compressor Pump
without a pulley guard in place.
Checking the Oil
Check the oil level before operation.
Fill the Pump Crankcase with air SAE
30W non-detergent compressor oil
(sold separately).
Tool
Shut
Off
Valve
Quick
Coupler
Coupler
Plug
Quick
Coupler
FilterOiler
Regulator with
Pressure Gauge
Coupler
Plug
Air Hose
on Reel
Air
Compressor
Sample Air Line Setup
Using the above diagram as a guide,15.
connect a regulator valve, an inline
shut off valve and a 1/4” NPT air
hose to the Quick Coupler (all sold
separately). The air hose must be
long enough to reach the work area
with enough extra length to allow free
movement while working.
Note: An in-line shutoff ball valve is an
important safety device because it
controls the air supply even if the
air hose is ruptured. The shutoff
valve should be a ball valve
because it can be closed quickly.
IMPORTANT: Running the Air
Compressor Pump with no oil or
low oil will cause damage to the
equipment and void the warranty.
Crankcase (16)
Oil Sight Glass (22)
OIL LEVEL
OVERFILL
FULL
LOW
Figure 2
The oil level should be at the center
of the “full” level on the oil level sight
glass, as shown in Figure 2 above.
Add oil as needed to maintain this
level. Do not let the oil level go
below the center dot (LOW as shown
above) and do not overll the oil
so that it is above the center dot
(OVERFILL as shown above) on the
sight glass.
To add oil:
Depending on the tool which you will 16.
be using with this compressor, you
may need to incorporate additional
components, such as an in-line oiler,
a lter, or a dryer. Consult your air
tool’s manual for needed accessories.
Remove the Oil Fill Screw (13).a.
Using a funnel to avoid spills, pour b.
enough oil into the Pump Crankcase
to reach the “full” level in the Oil
Sight Glass.
Replace the Oil Fill Screw (13).c.
REV 09j
Page 11For technical questions, please call 1-800-444-3353.SKU 93785
Page 12
Note: SAE 30W non-detergent Air
Compressor Oil (sold separately) is
recommended for use with this pump.
Open the in-line Shutoff Valve.8.
Turn the Power Switch ON. 9.
If uncertain which oil to use, please
call Harbor Freight Tools customer
service at 1-800-444-3353 for
assistance.
Change the compressor oil after
the rst hour of use to remove any
debris.
WARNING! To prevent serious injury from
burns: Do not add or change the
oil while the motor is in operation.
Allow the components to cool before
replacing oil.
GENERAL OPERATING
INSTRUCTIONS
Read the ENTIRE IMPORTANT
SAFETY INFORMATION
section at the beginning of this
manual including all text under
subheadings therein before set
up or use of this product.
Close the Drain Valve.1.
Make sure all nuts and bolts are tight.2.
Check for oil leaks and check the oil 3.
level (See Checking the Oil).
Close the in-line Shutoff Valve 4.
between the compressor and the air
hose.
Make sure the air tool’s throttle or 5.
switch is in the off position.
Connect the air tool to the air hose. 6.
Plug the Air Compressor Power Cord 7.
into a grounded 120 V electrical
outlet.
REV 09j
Allow the Air Compressor to build up 10.
pressure until it cycles off.
Check that the V-belt does not vibrate 11.
and listen for abnormal noise, air
leaks or vibration.
If there is a problem, turn power off 12.
and release air pressure from the line
before attempting repairs.
Note: At the beginning of the day’s rst
use of the Air Compressor, check for
air leaks by applying soapy water to
connections while the Air Compressor
is pumping and after pressure
cut-out. Look for air bubbles. If air
bubbles are present at connections,
tighten connections. Do not use the
air compressor unless all connections
are air tight, air leaks will cause the
compressor to operate too often,
increasing wear on the compressor.
Note: As long as the Power Switch is ON,
the operation of the Air Compressor
is automatic, controlled by an internal
pressure switch. The Compressor
will turn on automatically when the
air pressure drops to the minimum
PSI as indicated on the Pressure
Gauge, and will turn off automatically
when the air pressure reaches
the maximum PSI as indicated.
IMPORTANT: The internal pressure
switch is not user adjustable, do not
make changes to the air pressure
settings of the internal pressure
switch. Any change to the automatic
pressure levels may cause excess
pressure to accumulate, causing a
hazardous situation.
Page 12For technical questions, please call 1-800-444-3353.SKU 93785
Page 13
Adjust the Air Compressor’s Pressure 13.
Regulator so that the air output is
enough to properly power the tool,
but the output will not exceed the
tool’s maximum air pressure at any
time. Turn the knob clockwise to
increase the pressure and counterclockwise to decrease pressure.
Adjust the pressure gradually, while
checking the air output gauge to set
the pressure.
Use the air tool as needed.14.
After the job is complete, turn the 15.
Power Switch OFF.
Unplug the Air Compressor.16.
Close the in-line Shutoff Valve.17.
Bleed air from the tool then 18.
disconnect the tool.
Turn the Drain Valve, at the bottom 19.
of the Tank, two turns to release any
built-up moisture and the internal
tank pressure. Close the valve after
moisture has drained out. Do not
remove the Drain Valve.
MAINTENANCE AND
SERVICING
Procedures not specically
explained in this manual
must be performed only by a
qualied technician.
TO PREVENT
SERIOUS INJURY
FROM ACCIDENTAL
OPERATION:
Turn off and unplug the motor
before performing any
inspection, maintenance, or
cleaning procedures.
TO PREVENT SERIOUS
INJURY FROM MOTOR
FAILURE:
Do not use damaged
equipment. If abnormal noise
or vibration occurs, have the
problem corrected before
further use.
Cleaning, Maintenance, and
Lubrication
Clean, then store the Air Compressor 20.
indoors.
Emergency Depressurization
If it is necessary to quickly
depressurize the tank, turn the motor
OFF. Then, pull the Safety Valve to
quickly release stored air pressure.
BEFORE EACH USE,1. inspect the
general condition of the unit. Check
for loose hardware, misalignment or
binding of moving parts, damaged
belts, cracked or broken parts,
damaged electrical wiring, and any
other condition that may affect its
safe operation.
AFTER USE,2. wipe external surfaces
of the unit with a clean cloth.
3. WARNING! If the supply cord
of this unit is damaged, it must
be replaced only by a qualied
service technician.
REV 09j
Page 13For technical questions, please call 1-800-444-3353.SKU 93785
Page 14
Maintenance Schedule
Oil Maintenance
Following are general guidelines for
maintenance checks of the unit.
Note: The working environment and
frequency of use can affect how often
you will need to check components
and perform maintenance
procedures.
Daily:
Check oil level.a.
Check for oil leaks.b.
Make sure all fasteners are tight.c.
Drain moisture from air tank.d.
Check for abnormal noise or e.
vibration.
Check for air leaks.f.
*
Inspect drive belt.g.
Wipe off any oil or dirt from the h.
components.
**
Weekly:
Inspect Air Filter.a.
Inspect Oil Breather Plug (15).b.
Check the oil periodically for clarity.
Replace oil if it appears milky or if
debris is present, or every 6 months,
or 100 hours of runtime, whichever
comes rst. In harsh environments
such as high heat or high humidity,
you will need to replace the oil more
frequently.
WARNING: Risk of personal injury hazard.
Allow Air Compressor to cool before
changing the oil.
To drain the oil from the Pump
Crankcase:
Place a container under the Oil Drain a.
Bolt (24).
Remove the Oil Breather Plug (15) b.
to allow air ow into the Pump.
Remove the Oil Drain Bolt, allowing c.
the oil to drain into the container.
When the oil is completely drained d.
from the Pump, replace the Oil Drain
Bolt.
Monthly:
Inspect Safety Valve.a.
Check/adjust belt tension.b.
Every 6 months or 100 Operation
Hours:
Replace Pump oil.
***
* To check for air leaks, apply soapy water
to joints while the tank is pressurized. Look
for air bubbles.
** To clean the unit, wipe with a damp
cloth, using a mild detergent or mild
solvent.
*** Use Air Compressor Oil only (sold
separately - SKU 95048).
Fill the Pump with new compressor e.
oil to the FULL level on the Oil Sight
Glass.
Replace and tighten the Oil Breather f.
Plug.
Clean off any spilled oil.g.
Discard the old oil according to local, h.
state and federal regulations.
Draining Moisture from the Tank
The Drain Valve is located under the
Tank. It must be accessed daily to
release all trapped air and moisture
from the Tank. This will eliminate
condensation which can cause tank
corrosion.
REV 09j
Page 14For technical questions, please call 1-800-444-3353.SKU 93785
Page 15
Note: Do not open the Drain Valve so that
more than four threads are showing.
To empty the air and condensation:
Make sure the Power switch of the a.
compressor is off.
Place a collection pan under the b.
Drain Valve.
Unthread the Drain Valve two or c.
three turns ONLY.
When all the pressure and moisture d.
is released, close the Drain Valve.
Air Filter Maintenance
Check the Air Filter weekly to see if
it needs replacement. If working in
dirty environments, you may need
to replace the lter more often. To
replace the Air Filter:
Remove any cover that blocks a.
access to the Air Filter.
Remove the Air Filter.b.
Replace with a new Air Filter.c.
Replace the cover.d.
Page 15For technical questions, please call 1-800-444-3353.SKU 93785
Page 16
Troubleshooting
Problem Possible Causes Likely Solutions
Compressor does
not start or restart
Compressor builds
pressure too slowly
Compressor not
building enough air
pressure
High Oil
Consumption
Incorrect power supply.1.
No power at outlet. 2.
Power cord not plugged in 3.
properly.
Thermal overload switch 4.
tripped.
Building power supply circuit 5.
tripped or blown fuse.
Tanks are pressurized.6.
Cord wire size is too small or 7.
cord is too long to properly
power compressor.
Compressor needs service.8.
Incorrect power supply.1.
Crankcase overlled with oil or 2.
oil too thick.
Working environment too cold. 3.
Safety valve needs service. 4.
Loose ttings.5.
Filters need cleaning/replacing. 1.
Crankcase oil too thick. 2.
Check Valve needs service.3.
Compressor not large enough 4.
for job.
Loose ttings. 5.
Hose or hose connections not 6.
adequate.
High altitude reducing air 7.
output.
Crankcase oil too thin. 1.
Unit not on level surface.2.
Crankcase vent clogged.3.
Check that circuit matches compressor requirements.1.
Reset circuit breaker, or have outlet serviced by a 2.
qualied technician.
Check that cord is plugged in securely. 3.
Turn off Tool. Turn off Compressor and wait for it to 4.
cool down. Press reset button. Resume operation.
Reset circuit or replace fuse. Check for low voltage 5.
conditions. It may be necessary to disconnect other
electrical appliances from the circuit or move the
compressor to its own circuit.
Fully bleed tanks of air.6.
Use larger diameter or shorter extension cord or 7.
eliminate extension cord. See Recommended Wire
Gauge for Extension Cords in Safety section.
Have unit inspected by a qualied technician.8.
Check that circuit matches compressor requirements.1.
Drain oil and rell to proper level with recommended 2.
oil.
Move unit to a warmer location. Check that 3.
recommended oil is in crankcase.
Listen for air leaking from valve. If leaking 4.
replace with identical valve with same rating.
Reduce air pressure, then check all ttings with a soap 5.
solution for air leaks and tighten as needed. Do not
overtighten.
Check inlet and outlet lters. Clean and/or replace as 1.
needed.
Drain oil and rell to proper level with recommended 2.
oil.
Clean or replace, as needed.3.
Check if accessory SCFM is met by Compressor. If 4.
Compressor cannot supply enough air ow (SCFM),
you need a larger Compressor.
Reduce air pressure, then check all ttings with a soap 5.
solution for air leaks and tighten as needed. Do not
overtighten.
Replace with larger hose and/or hose connections. 6.
You may need a larger compressor if you are situated 7.
in a high altitude location.
Drain oil and rell to proper level with recommended 1.
oil.
Reposition unit on a level surface.2.
Clean Crankcase vent.3.
Follow all safety precautions whenever diagnosing or servicing the
compressor. Disconnect power supply before service.
REV 09j
Page 16For technical questions, please call 1-800-444-3353.SKU 93785
Page 17
Problem Possible Causes Likely Solutions
Overheating Filters need cleaning/replacing. 1.
Compressor
starts and stops
excessively
Crankcase oil too thin or 2.
incorrect type.
Crankcase oil level too low.3.
Unusually dusty environment. 4.
Cord is too small of a gauge or 5.
too long to handle compressor.
Unit not on level surface.6.
Compressor not large enough 1.
for the job.
Loose ttings.2.
Check inlet and outlet lters. Clean and/or replace as 1.
needed.
Drain oil and rell to proper level with recommended 2.
oil.
Add oil to proper level, check for leaks.3.
Clean and/or replace lters more often or move unit to 4.
cleaner environment.
Increase cord size or use shorter length extension 5.
cord, or eliminate extension cord. See Recommended
Wire Gauge for Extension Cords in Safety section.
Reposition unit on a level surface.6.
Check if accessory SCFM is met by Compressor. If 1.
Compressor doesn’t reach accessory SCFM, you need
a larger Compressor.
Reduce air pressure, then check all ttings with a soap 2.
solution for air leaks and tighten as needed. Do not
overtighten.
Excessive noise Crankcase overlled with oil 1.
or oil is incorrect thickness or
type.
Crankcase oil level too low.2.
Loose or damaged belt guard.3.
Loose ttings. 4.
Unit not on level surface.5.
Moisture in
discharge air
Oil in discharge air Crankcase oil too thin or 1.
Safety Valve “pops” Safety valve needs service. Pull and release the test ring of safety valve. If it still pops,
Air leaks from pump
or ttings
Too much moisture in air. Install inline air lter/dryer, and/or relocate to less humid
crankcase overlled with oil.
Crankcase vents clogged.2.
Loose ttings.
Drain oil and rell to proper level with recommended 1.
oil.
Add oil to proper level, check for leaks.2.
Tighten or replace belt guard.3.
Reduce air pressure, then check all ttings with a soap 4.
solution for air leaks and tighten as needed. Do not
overtighten.
Reposition unit on a level surface.5.
environment.
Drain oil and rell to proper level with recommended 1.
oil.
Clean Crankcase vents.2.
replace.
Reduce air pressure, then check all ttings with a
soap solution for air leaks and tighten as needed. Do
not overtighten.
Air leaks from tank Defective or rusted tank. Have tank replaced by a qualied technician.
Follow all safety precautions whenever diagnosing or servicing the
compressor. Disconnect power supply before service.
REV 09j
Page 17For technical questions, please call 1-800-444-3353.SKU 93785
Page 18
PLEASE READ THE FOLLOWING CAREFULLY
THE MANUFACTURER AND/OR DISTRIBUTOR HAS PROVIDED THE PARTS LIST AND ASSEMBLY
DIAGRAM IN THIS MANUAL AS A REFERENCE TOOL ONLY. NEITHER THE MANUFACTURER OR
DISTRIBUTOR MAKES ANY REPRESENTATION OR WARRANTY OF ANY KIND TO THE BUYER THAT
HE OR SHE IS QUALIFIED TO MAKE ANY REPAIRS TO THE PRODUCT, OR THAT HE OR SHE IS
QUALIFIED TO REPLACE ANY PARTS OF THE PRODUCT. IN FACT, THE MANUFACTURER AND/
OR DISTRIBUTOR EXPRESSLY STATES THAT ALL REPAIRS AND PARTS REPLACEMENTS SHOULD
BE UNDERTAKEN BY CERTIFIED AND LICENSED TECHNICIANS, AND NOT BY THE BUYER. THE
BUYER ASSUMES ALL RISK AND LIABILITY ARISING OUT OF HIS OR HER REPAIRS TO THE
ORIGINAL PRODUCT OR REPLACEMENT PARTS THERETO, OR ARISING OUT OF HIS OR HER
INSTALLATION OF REPLACEMENT PARTS THERETO.
PARTS LIST
Part Description Qty
1 Washer 6
2 Bolt 6
3 Screw 2
4 Air Filter 1
5 Cylinder Head 1
6 Air Outlet 1
7 Gasket Valve Seat 1
8 Valve Seat 2
9 Gasket Valve Seat 4
10 Valve Plate 4
11 Gasket 1
12 Cylinder 1
13 Oil Fill Screw 1
13-A O-Ring 1
14 Cylinder Gasket 1
15 Oil Breather Plug 1
15-A O-Ring 1
16 Crankcase 1
17 Gasket 1
18 Bearing Cover 1
19 Spring Washer 6
19-A Screw 6
20 Spring Washer 8
21 Screw 8
22 Oil Sight Glass 1
Part Description Qty
23 Oil Window Gasket 1
24 Oil Drain Bolt 1
25 Seal 1
26 Gasket 1
27 Base Cover 1
28 Bearing #6205 2
29 Crankshaft 1
30 Oil Seal 1
31 End Cover 1
32 Bolt 1
33 Spring Washer 4
34 Washer 1
35 Belt Wheel 1
36 Nut 4
37 Bolt 4
38 Connecting Rod 2
39 Piston Pin 2
40 Lock Ring 4
41 Piston 2
42 Piston Oil Ring 2
43 Piston Compression Ring 4
44 Flare Nut 1
45 Screw 2
46 Gasket 1
REV 09j
Page 18For technical questions, please call 1-800-444-3353.SKU 93785
Page 19
ASSEMBLY DIAGRAM
Record Product’s Serial Number Here:
Note: If product has no serial number, record month and year of purchase instead.
Note: Some parts are listed and shown for illustration purposes only, and are not
available individually as replacement parts.
Page 19For technical questions, please call 1-800-444-3353.SKU 93785
REV 09j
Page 20
LIMITED 90 DAY WARRANTY
Harbor Freight Tools Co. makes every effort to assure that its products meet high
quality and durability standards, and warrants to the original purchaser that this product
is free from defects in materials and workmanship for the period of 90 days from the
date of purchase. This warranty does not apply to damage due directly or indirectly,
to misuse, abuse, negligence or accidents, repairs or alterations outside our facilities,
criminal activity, improper installation, normal wear and tear, or to lack of maintenance.
We shall in no event be liable for death, injuries to persons or property, or for incidental,
contingent, special or consequential damages arising from the use of our product.
Some states do not allow the exclusion or limitation of incidental or consequential
damages, so the above limitation of exclusion may not apply to you. THIS WARRANTY
IS EXPRESSLY IN LIEU OF ALL OTHER WARRANTIES, EXPRESS OR IMPLIED,
INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS.
To take advantage of this warranty, the product or part must be returned to us
with transportation charges prepaid. Proof of purchase date and an explanation of the
complaint must accompany the merchandise. If our inspection veries the defect, we
will either repair or replace the product at our election or we may elect to refund the
purchase price if we cannot readily and quickly provide you with a replacement. We will
return repaired products at our expense, but if we determine there is no defect, or that
the defect resulted from causes not within the scope of our warranty, then you must
bear the cost of returning the product.
This warranty gives you specic legal rights and you may also have other rights
which vary from state to state.
3491 Mission Oaks Blvd. • PO Box 6009 • Camarillo, CA 93011 • (800) 444-3353
Page 20For technical questions, please call 1-800-444-3353.SKU 93785
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