MQ Multiquip MQD2HA User manual

OPERATION MANUAL
THIS MANUAL MUST ACCOMPANY THE EQUIPMENT AT ALL TIMES.
MODELS
MQD2HA
MQD3HA
DIAPHRAGM PUMP
(HONDA GX120UT1QX2 GASOLINE ENGINE)
Revision #1 (10/08/20)
To find the latest revision of this publication or
associated parts manual, visit our website at:
www.multiquip.com

PAGE 2 — MQD2HA/3HA DIAPHRAGM PUMP • OPERATION MANUAL — REV. # 1 (10/08/20)
PROPOSITION 65 WARNING

MQD2HA/3HA DIAPHRAGM PUMP • OPERATION MANUAL — REV. # 1 (10/08/20) — PAGE 3
TABLE OF CONTENTS
MQD2H/3H Diaphragm
Pumps
Proposition 65 Warning ........................................... 2
Safety Information ................................................ 4-6
Specifications/Performance Curve .......................... 7
Dimensions.............................................................. 8
General Information................................................. 9
Pump Components........................................... 10-11
Basic Engine.......................................................... 12
Inspection (Engine)................................................ 13
Setup ................................................................ 14-15
Operation.......................................................... 16-17
Maintenance (Pump) ........................................ 18-21
Maintenance (Engine) ...................................... 22-24
Storage .................................................................. 25
Troubleshooting (Engine).................................. 26-27
Troubleshooting (Pump) ................................... 27-28
NOTICE
Specifications and part numbers are subject to change
without notice.

PAGE 4 — MQD2HA/3HA DIAPHRAGM PUMP • OPERATION MANUAL — REV. # 1 (10/08/20)
SAFETY INFORMATION
Do not operate or service the equipment before reading
the entire manual. Safety precautions should be followed
at all times when operating this equipment.
Failure to read and understand the safety
messages and operating instructions could
result in injury to yourself and others.
SAFETY MESSAGES
The four safety messages shown below will inform you
about potential hazards that could injure you or others.The
safety messages specifically address the level of exposure
to the operator and are preceded by one of four words:
DANGER, WARNING, CAUTION
or NOTICE.
SAFETY SYMBOLS
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
Indicates a hazardous situation which, if not avoided,
COULD result in MINOR or MODERATE INJURY.
NOTICE
Addresses practices not related to personal injury.
Potential hazards associated with the operation of this
equipment will be referenced with hazard symbols which
may appear throughout this manual in conjunction with
safety messages.

MQD2HA/3HA DIAPHRAGM PUMP • OPERATION MANUAL — REV. # 1 (10/08/20) — PAGE 5
SAFETY INFORMATION
GENERAL SAFETY
CAUTION

NEVER operate this equipment without proper protective
clothing, shatterproof glasses, respiratory protection,
hearing protection, steel-toed boots and other protective
devices required by the job or city and state regulations.

Avoid wearing jewelry or loose fitting clothes that may
snag on the controls or moving parts as this can cause
serious injury.

NEVER operate this equipment when not
feeling well due to fatigue, illness or when
under medication.

NEVER operate this equipment under the
influence of drugs or alcohol.

ALWAYS clear the work area of any debris, tools, etc.
that would constitute a hazard while the equipment is
in operation.

No one other than the operator is to be in the working
area when the equipment is in operation.

DO NOT use the equipment for any purpose other than
its intended purposes or applications.
NOTICE

This equipment should only be operated by trained and
qualified personnel 18 years of age and older.

Whenever necessary, replace nameplate, operation and
safety decals when they become difficult read.

Manufacturer does not assume responsibility for any
accident due to equipment modifications. Unauthorized
equipment modification will void all warranties.
NEVER
use accessories or attachments that are not
recommended by Multiquip for this equipment. Damage
to the equipment and/or injury to user may result.
ALWAYS know the location of the nearest
fire extinguisher.
ALWAYS know the location of the nearest
first aid kit.
ALWAYS know the location of the nearest phone or
keep
a phone on the job site.
Also, know the phone numbers
of the nearest ambulance, doctor and
fire department.
This information will be invaluable in the case of an
emergency.

PAGE 6 — MQD2HA/3HA DIAPHRAGM PUMP • OPERATION MANUAL — REV. # 1 (10/08/20)
SAFETY INFORMATION
PUMP SAFETY
DANGER

NEVER operate the equipment in an explosive
atmosphere or near combustible materials.An
explosion or fire could result causing severe
bodily harm or even death.
WARNING

Accidental starting can cause severe injury
or death. ALWAYS place the ON/OFF
switch in the OFF position.

DO NOT place hands or fingers inside
pump when pump is running.

NEVER disconnect any emergency or
safety devices. These devices are intended for operator
safety. Disconnection of these devices can cause severe
injury, bodily harm or even death. Disconnection of any
of these devices will void all warranties.
CAUTION

DO NOT restrict the flow of the discharge hose as it may
cause overheating.

Be careful of discharge whipping under pressure.
NOTICE

NEVER operate the pump at extreme angles or slopes.

DO NOT allow up to freeze in water.

NEVER leave an open pump chamber unattended.

ALWAYS keep the machine in proper running condition.

DO NOT attempt to thaw-out a frozen pump by using
a torch or other source of flame. Application of heat in
this manner may heat the oil in the seal cavity above the
critical point, causing pump damage.

DO NOT pump water greater than 104º F.

DO NOT pump liquids containing acid or alkali.

ALWAYS check strainer before pumping. Make sure
strainer is not clogged. Remove any large objects, dirt
or debris from the strainer to prevent clogging.

ALWAYS use a large basket strainer when pumping
water that contains large debris.
ALWAYS
flush pump (clean) after use when pumping
water concentrated with heavy debris. It is very important
to always flush the pump before turning it off to prevent
clogging.

Fix damage to machine and replace any broken parts
immediately.
ALWAYS
store equipment properly when it is not being
used. Equipment should be stored in a clean, dry location
out of the reach of children and unauthorized personnel.
NEVER
lubricate components or attempt service on a
running machine.
ALWAYS
allow the machine a proper amount of time to
cool before servicing.
Keep machine in proper running condition.
LIFTING SAFETY
CAUTION

When raising or lowering of the pump is required, always
attach an adequate rope or lifting device to the correct
lifting point (handle) on the pump.
NOTICE
DO NOT lift machine to unnecessary heights.
NEVER lift the equipment while the engine is running.
TRANSPORTING SAFETY
NOTICE
ALWAYS shutdown pump before transporting.
ALWAYS
tie down equipment during transport by
securing the equipment with rope.
ENVIRONMENTAL SAFETY
NOTICE
Dispose of hazardous waste properly.
Examples of potentially hazardous waste
are used motor oil, fuel and fuel filters.
DO NOT
use food or plastic containers to dispose of
hazardous waste.
DO NOT
pour waste, oil or fuel directly onto the ground,
down a drain or into any water source.

MQD2HA/3HA DIAPHRAGM PUMP • OPERATION MANUAL — REV. # 1 (10/08/20) — PAGE 7
SPECIFICATIONS
Table 1. Specifications (Engine)
Engine
Model HONDA GX120UT1QX2
Type Air-cooled 4 stroke, Single Cylinder, OHV,
Horizontal Shaft Gasoline Engine
Bore x Stroke 2.4 in. x 1.7 in.
(60 mm x 42 mm)
Displacement 119 cc (7.2 cu-in)
Max Output 4.0 H.P./2,750 R.P.M.
Fuel Tank Capacity 0.66 US gal. (2.5 liters)
Fuel Unleaded Automobile Gasoline
Lube Oil Capacity 0.63 quart (0.60 liter)
Speed Control Method Centrifugal Fly-weight Type
Starting Method Recoil Start
Dimension (L x W x H) 11.7 x 13.4 x 12.5 in. (297 x 341 x 318 mm)
Dry Net Weight 28.7 lbs (13 Kg.)
Table 2. Specifications (Pump)
Pump
Model MQD2HA MQD3HA
Type Diaphragm Pump Diaphragm Pump
Suction & Discharge Size 2.00 in. (50.8 mm) 3.00 in. (76.2 mm)
Maximum Pumping Capacity 50 gallons/minute
(189.2 liters/minute)
90 gallons/minute
(340.7 liters/minute)
Max. Solids Diameter 1.50 in. (38.1 mm) 1-5/8 in (41.275 mm)
Maximum Sunction Lift 26 ft. (7.92 meters) 26 ft. (7.92 meters)
Max. Head 25 ft. (7.62 meters) 25 ft. (7.62 meters)
Dry Net Weight 140 lbs. (63 Kg.) 160 lbs. (72 Kg.)
Figure 1. MQD2HA/MQD3HA Performance Curve

PAGE 8 — MQD2HA/3HA DIAPHRAGM PUMP • OPERATION MANUAL — REV. # 1 (10/08/20)
DIMENSIONS
Figure 2. MQD2HA/3HA Dimensions
GREASE
CONNECTING
ROD BEARING
MONTHLY
C
D E
A
B
Table 3. Dimensions
Model A
Length
B
Height
C
Width
D
Discharge
E
Suction
MQD2HA 39 in
(99.06 cm.)
27.53 in.
(69.93 cm.)
25.68 in.
(65.23 cm.)
7.34 in.
(18.64 cm.)
5.62 in.
(14.27 cm.)
MQD3HA 41.5 in.
(105.41 cm.)
22 in.
(55.88 cm.)
30 in.
(76.2 cm.)
6.2 in.
(15.75 cm.)
6.3 in.
(16 cm.)

MQD2HA/3HA DIAPHRAGM PUMP • OPERATION MANUAL — REV. # 1 (10/08/20) — PAGE 9
Elevation
Higher elevations will effect the performance of the pump.
Due to less atmospheric pressure at higher altitudes,
pumps do not have the priming ability that they have at
sea level. This is due to the “thinner air” or lack of oxygen
at higher altitudes.
A general rule of thumb is that for every 1,000 feet of
elevation above sea level a pump will lose one foot of
priming ability.
For example, in Flagstaff, Arizona where the elevation is
approximately 7,000 feet, the pump would have a suction
lift of only 18 feet rather than the 25 feet at sea level.Table 4
shows suction lift at various elevations.
Table 4. Suction Lift at Various Elevations
Altitude
Feet
(Meters)
Suction Lift in Feet (Meters)
Sea Level 10.0 (3.048) 15.0 (4.572) 20.0 (6.096) 25.0 (7.620)
2,000 (610) 8.80 (2.680) 13.2 (4.023) 17.6 (5.364) 22.0 (6.705)
4,000 (1,219) 7.80 (2.377) 11.7 (3.566) 15.6 (4.754) 19.5 (5.943)
6,000 (1,829) 6.90 (2.103) 10.4 (3.169) 13.8 (4.206) 17.3 (5.273)
8,000 (2,438) 6.20 (1.889) 9.30 (2.834) 12.4 (3.779) 15.5 (4.724)
10,000 (3,048) 5.70 (1.737) 8.60 (2.621) 11.4 (3.474) 14.3 (4.358)
Table 5 shows percentage drops in performance as
elevation increases.
Table 5. Performance Loss at Various Elevations
Altitude
Feet (Meters) Discharge Flow Discharge Head
Sea Level 100% 100%
2,000 (610) 97% 95%
4,000 (1,219) 95% 91%
6,000 (1,829) 93% 87%
8,000 (2,438) 91% 83%
10,000 (3,048) 88% 78%
GENERAL INFORMATION
APPLICATION
The MQD2H The models MQD2HA & MQD3HA diaphragm
pumps are designed to be used on selected dewatering
applications. The suction and discharge ports are NPT
threaded and are 2” diameter for the MQD2HA and 3” in
diameter for the MQD3HA.
The pumping flow rates (GPM) are dependent on the
application, hose lengths, operating elevation, and fluid
viscosity.
Power Plant
These diaphragm pumps are powered by a 4.0 horsepower
air cooled, 4-stroke, single cylinder HONDA GX120 gasoline
engine that incorporates a low “Oil Alert Feature”. The drive
shaft of the engine is coupled to an offset connecting rod
that is coupled to a flexible diaphragm.The connecting rod
alternately raises (expands) and lowers (contracts) the
diaphragm at a rate of 60 cycles per minute at maximum
engine RPM (2,750).
Oil Alert Feature
In the event of low oil or no oil, the HONDA GX120 engine
has a built-in oil alarm engine shut-down feature. In the
event the oil level is low the engine will automatically shut
down.
Suction Lift
This pump is intended to be used for dewatering applications
and is capable of suction lifts up to 25 feet at sea level. For
optimal suction lift performance keep the suction hose or
line as short as possible. In general, always place the pump
as close to the water as possible.
Pump Support
The pump should always be placed on solid stationary
ground in a level position.
NEVER place the pump on soft soil. The suction hose or
pipe connection should always be checked for tightness
and leaks. A small suction leak in the hose or fittings could
prevent the pump from priming.

PAGE 10 — MQD2HA/3HA DIAPHRAGM PUMP • OPERATION MANUAL — REV. # 1 (10/08/20)
Figure 3. MQD2HA-3HA Key Components
GREASE
CONNECTING
ROD BEARING
MONTHLY
5
8
7
4
12
43
6
4
9
GEARBOX
INPUT HALF
10
11
PUMP COMPONENTS
Contact your nearest Multiquip
dealer for quick disconnect
hoses and fittings.

MQD2HA/3HA DIAPHRAGM PUMP • OPERATION MANUAL — REV. # 1 (10/08/20) — PAGE 11
PUMP COMPONENTS
Figure 3 shows key components of the MQD2HA/MQD3HA.
1. Pump — The Multiquip Models MQD2HA and
MQD3HA are 2-inch and 3-inch diaphragm pumps
respectively and are used in general dewatering
applications. Typical dewatering applications consist
of cleaning out cesspools and septic tanks, draining
slow seepage from small excavations, trenches and
construction sites, or pumping out industrial waste.
2. Priming Plug/Suction Priming Chamber — To help
facilitate faster priming operations, fill chamber with
clean water and secure priming plug.
3. Discharge Port — Connect either a 2-inch or 3-inch
discharge hose to this port depending on pump model.
4. NPT Connection — Used to secure the hose to the
inlet and outlet ports on the pump.
5. Discharge Hose — Connect a flexible rubber
hose to the discharge port on the pump. Make sure
that the hose lays flat and is not kinked. Use only
recommended type discharge hose. Contact Multiquip
parts department for ordering information.
6. Suction Port — Connect either a 2-inch or 3-inch inlet
hose to this port depending on pump model.
7. Suction Hose — Connect a flexible rubber hose to
the suction port on the pump. Make sure that the hose
lays flat and is not kinked. Use only recommended type
suction hose. Contact Multiquip parts department for
ordering information.
8. Strainer — Always attach a strainer to bottom side of
the suction hose to prevent large objects and debris
from entering the pump. Strainer should be positioned
so that it will remain completely under water.
9. Transmission Oil Fill Plug — Remove this plug to add
SAE 80/90 EP (API GL-5) gear oil to the transmission.
Transmission oil capacity is 22 ounces (651 ml).
10. Connecting Rod — Grease connecting rod bearing
every 25 hours of operation. Remove plunger guard to
gain access to bearing.
11. Plunger Guard — Protects connecting rod, waterbox,
diaphragm and other associated components.

PAGE 12 — MQD2HA/3HA DIAPHRAGM PUMP • OPERATION MANUAL — REV. # 1 (10/08/20)
3. Fuel Tank — Holds unleaded gasoline. For additional
information refer to engine owner's manual.
4. Engine ON/OFF Switch — ON position permits engine
starting, OFF position stops engine operations.
5. Recoil Starter (pull rope) — Manual-starting method.
Pull the starter grip until resistance is felt, then pull
briskly and smoothly.
6. Fuel Valve Lever — OPEN to let fuel flow, CLOSE to
stop the flow of fuel.
7. Oil Drain Plug — Remove this plug to remove oil from
the engine's crankcase.
8. Dipstick/Oil Filler Cap — Remove this cap to
determine if the engine oil is low. Add oil through this
filler port as recommended in Table 1.
9. Choke Lever — Used in the starting of a cold engine,
or in cold weather conditions. The choke enriches the
fuel mixture.
10. Spark Plug — Provides spark to the ignition system.
Set spark plug gap to 0.6 - 0.7 mm (0.028 - 0.031 inch).
Clean spark plug once a week.
11. Muffler — Used to reduce noise and emissions.
12. Air Filter — Prevents dirt and other debris from
entering the fuel system. Remove wing-nut on top of
air filter cannister to gain access to filter element.
WARNING
Engine components can generate
extreme heat. To prevent burns,
DO NOT touch these areas while the
engine is running or immediately after
operating. NEVER operate the engine
with the muffler removed.
NOTICE
Operating the engine without an air filter, with a
damaged air filter, or a filter in need of replacement
will allow dirt to enter the engine, causing rapid engine
wear.
Figure 4. Engine Controls and Components
2
12
11
1
4
3
10
9
8
7
65
INITIAL SERVICING
The engine (See Figure 4) must be checked for proper
lubrication and filled with fuel prior to operation. Refer to the
manufacturers engine manual for instructions and details
of operation and servicing. The engine shown above is a
HONDA engine, operation for other types of engines may
vary somewhat.
1. Throttle Lever — Used to adjust engine RPM speed
(lever advanced forward SLOW, lever back toward
operator FAST)..
2. Fuel Filler Cap — Remove this cap to add unleaded
gasoline to the fuel tank. Make sure cap is tightened
securely. DO NOT over fill.
DANGER
Adding fuel to the tank should be done
only when the engine is stopped and
has had an opportunity to cool down.
In the event of a fuel spill, DO NOT
attempt to start the engine until the fuel
residue has been completely wiped up,
and the area surrounding the engine
is dry.
BASIC ENGINE

MQD2HA/3HA DIAPHRAGM PUMP • OPERATION MANUAL — REV. # 1 (10/08/20) — PAGE 13
INSPECTION (ENGINE)
CAUTION
DO NOT attempt to operate the pump
until the Safety Information, General
Information and Inspection sections
of this manual have been read and
thoroughly understood.
BEFORE STARTING
1. Read safety instructions at the beginning of manual.
2. Clean the pump, removing dirt and dust, particularly
the engine cooling air inlet, carburetor and air cleaner.
3. Check the air filter for dirt and dust. If air filter is dirty,
replace air filter with a new one as required.
4. Check carburetor for external dirt and dust. Clean with
dry compressed air.
5. Check fastening nuts and bolts for tightness.
Engine Oil Check
1. To check the engine oil level, place the pump on secure
level ground with the engine stopped.
2. Remove the filler dipstick from the engine oil filler hole
(See Figure 5) and wipe clean.
Figure 5. Engine Oil Dipstick (Removal)
DIPSTICK
3. Insert and remove the dipstick without screwing it into
the filler neck. Check the oil level shown on the dipstick.
4. If the oil level is low (See Figure 6), fill to the edge
of the oil filler hole with the recommended oil type
(Table 6). Maximum oil capacity is 0.63 quarts
(0.6 liters).
Figure 6. Engine Oil DipStick (Oil Level
Fuel Check
1. Remove the gasoline cap located on top of fuel tank.
2. Visually inspect to see if the fuel level is low. If fuel is
low, replenish with unleaded fuel.
3. When refueling, be sure to use a strainer for filtration.
DO NOT top-off fuel. Wipe up any spilled fuel
immediately!
UPPER LIMIT
LOWER LIMIT
Table 6. Oil Type
Season Temperature Oil Type
Summer 25°C or Higher SAE 10W-30
Spring/Fall 25°C~10°C SAE 10W-30/20
Winter 0°C or Lower SAE 10W-10
DANGER
Motor fuels are highly flammable and can
be dangerous if mishandled. DO NOT
smoke while refueling. DO NOT attempt
to refuel the pump if the engine is hot
or running.

PAGE 14 — MQD2HA/3HA DIAPHRAGM PUMP • OPERATION MANUAL — REV. # 1 (10/08/20)
BEFORE STARTING
1. Read safety instructions at the beginning of manual.
2. Place pump as near to the water as possible, on a firm,
flat and level surface.
HOSES AND CLAMPS
1. Check that all hoses are securely attached to the
pump. Make certain suction hose (Figure 2) does not
have any air leakage. Use teflon tape or pipe dope on
NPT threads.
2. Remember suction hoses must be rigid enough not to
collapse when the pump is in operation.
3. Check that the discharge hose (Figure 2) is not
restricted. Place hose so that it lays as straight as it is
possible on the ground. Remove any twists or sharp
bends from hose which may block the flow of water.
4. The discharge hose is usually a collapsible (thin-
walled) hose, however if a thin-walled discharge hose
is not available, a rigid suction hose can be substituted
in its place.
5. Make sure the suction strainer (Figure 2) is clean
and securely attached to the water end of the suction
hose. The strainer is designed to protect the pump
by preventing large objects from being pulled into the
pump.
WARNING
DO NOT open fill cap if pump is hot! Water inside may
be under pressure.
NOTICE
Suction and discharge hoses are available from
Multiquip. Contact your nearest dealer for more
information.
CAUTION
Transmission fluid needs to be added prior to operation.
CAUTION
The strainer should be positioned so it will remain
completely under water. Running the pump with the
strainer above water for long periods can damage the
pump.
HANDLE INSTALLATION
The MQD2HA/D3HA diaphragm pumps are completely
assembled except for the steering handle. Attach the
steering handle to the pump base as referenced below:
1. Align handle mounting holes with front holes on
gearbox feet as shown in Figure 7.
2. Insert 1/2"-13 hex screw (2) with 1/2" washer (2)
through hole opening in handle and attach to gearbox
feet.
3. Secure handle using two 1/2"-13 flange nuts. Tighten
securely.
Figure 7. Handle Installation
CAUTION
Failure to follow instructions and properly install handle,
mounting screws with washers, and torque mounting
screws, will result in damage or premature failure to
gearbox, base or other pump components.
1/2”
FLAT
WASHER
1/2”-13
HEX BOLT
HANDLE
GEARBOX
FEET
1/2”-13
FLANGE NUT
SETUP

MQD2HA/3HA DIAPHRAGM PUMP • OPERATION MANUAL — REV. # 1 (10/08/20) — PAGE 15
SETUP
GEAR REDUCTION OIL (TRANSMISSION)
1. Remove the the two 1/4"-20 X 3/4" hex flange screws
(Figure 9) that secure the plunger guard to the gearbox
feet. Set plunger guard aside.
2. Next, remove the transmission oil fill plug and o-ring
from gearbox input half as shown in Figure 8.
Figure 8. Transmission Oil Level
3. Fill with SAE 80/90 EP (API GL-5) gear oil to the proper
operating level.Transmission oil capacity is capacity is
22 ounces (651 ml).
4. Reinstall plunger guard and transmission oil level plug.
CAUTION
DO NOT pump flammable fluids, corrosive chemicals
or fluids containing toxic substances. These fluids can
create potentially dangerous health and environmental
hazards. Contact local authorities for assistance.
TRANSMISSION
OIL FILL
PLUG/OIL RING
FILL
WITH SAE 80/90
EP GEAR OIL
GEARBOX
INPUT
HALF
NOTICE
Diaphragm pumps will handle fluids containing
considerable solids (see Table 2 for maximum solids
diameter), however, if the mixture is too heavy to
be pumped, water must be added until the mixture
becomes sufficently fluid for pumping.
CONNECTING ROD BEARING LUBRICATION
1. Remove the two 1/4"-20 X 3/4" hex flange screws that
secure plunger guard to the gearbox feet (Figure 9).
Figure 9. Connecting Rod Bearing Lubrication
2. Next, remove plunger guard and set aside.
3. Grease connecting rod bearing thru the access hole
(Figure 8) every 25 hours of operation.
4. Use only premium lithium based grease, conforming
to NLG1 Grade #2 consistency.
5. Reinstall plunger guard.
HELPFUL HINTS
The capacity of this diaphragm pump will vary greatly
depending on the height of the suction lift and length of
the discharge hose. A discharge hose which is too small,
long or high will cause the following:
Excessive bulging of diaphragm on the down stroke.
Valves closing with a loud snap.
Rough operation.
Engine overloads and slow downs.
Reduced efficiency.
PLUNGER
GUARD
HEX
FLANGE
SCREW
70 FT-LBS
(9.6 KG-M)
PLUNGER
ARM
APPLY2OR 3 SHOTS
OF PREMIUM LITHIUM
BASE GREASE EVERY
25 HOURS OF OPERATION
LOCK
SCREW

PAGE 16 — MQD2HA/3HA DIAPHRAGM PUMP • OPERATION MANUAL — REV. # 1 (10/08/20)
OPERATION
STARTING THE ENGINE
1. Place the engine fuel valve lever (See Figure 10) to
the ON position.
Figure 10. Engine Fuel Valve Lever (ON Position)
2. Move the throttle lever (See Figure 11) to idle position.
Figure 11. Throttle Lever (Idle Position
3. Place the choke lever (See Figure 12) in the CLOSED
position if starting a cold engine.
Figure 12. Engine Choke Lever (Closed)
CAUTION
This section is intended to assist the operator with the
initial startup of the pump. It is extremely important that
this section be read carefully before attempting to use
the pump in the field.
FUEL VALVE
LEVER
ON
OFF
THROTTLE
LEVER
RUN IDLE
OPEN
CLOSE
CHOKE LEVER
4. Place the choke lever (See Figure 13) in the OPEN
position if starting a warm engine or the temperature
is warm.
Figure 13. Engine Choke Lever (Open)
5. Place the engine ON/OFF switch (See Figure 14) in
the ON position.
Figure 14. Engine ON/OFF Switch (ON Position)
6. Grasp the starter grip (See Figure 15) and slowly pull
it out.The resistance becomes the hardest at a certain
position, corresponding to the compression point. Pull
the starter grip briskly and smoothly for starting.
Figure 15. Starter Grip
7. If the engine has started and the choke lever was
moved to the CLOSED position to start the engine,
gradually move the choke lever to the OPEN position
(Figure 16) as the engine warms up. If the engine has
not started repeat steps 1 through 6.
OPEN
CLOSE
CHOKE LEVER
ON
OFF
ENGINE SWITCH
STARTER GRIP

MQD2HA/3HA DIAPHRAGM PUMP • OPERATION MANUAL — REV. # 1 (10/08/20) — PAGE 17
OPERATION
Figure 16. Choke Lever (Open)
8. Before the pump is placed in to operation, run the
engine for several minutes. Check for fuel leaks, and
noises that would associate with a lose component.
9. To begin pumping, place the throttle lever (See
Figure 17) in the RUN position. If water is not flowing
out of the discharge port, turn off the engine and check
for and clear any obstructions within the suction hose.
Figure 17. Throttle Lever (Run)
OPEN
CLOSE
CHOKE LEVER
THROTTLE
LEVER
RUN IDLE
NOTICE
Pump speed can be regulated with the engine throttle
control from full. volume, 65 strokes per pinute, to about
40 strokes per minute for lesser volume seepage.
Smoothest operation can be determined by trying
to pump at several speeds. Limit maximum speed to
65 strokes per minute of the diaphragm (2,800 RPM
engine speed).
STOPPING THE ENGINE
Normal Shutdown
1. Move the throttle lever to the IDLE position
(See Figure 18) and run the engine for three minutes
at low speed.
Figure 18. Throttle Lever (Idle)
2. After the engine cools, turn the engine ON/OFF switch
to the OFF position (See Figure 19).
Figure 19. Engine ON/OFF Switch (OFF)
3. Place the fuel shut-off lever (See Figure 20) in the
OFF position
Figure 20. Fuel Valve Lever (OFF)
Emergency Shutdown
1. Move the throttle lever quickly to the IDLE position, and
place the engine ON/OFF switch in the OFF position.
THROTTLE
LEVER
RUN IDLE
ON
OFF
ENGINE SWITCH
FUEL VALVE
LEVER
ON
OFF

PAGE 18 — MQD2HA/3HA DIAPHRAGM PUMP • OPERATION MANUAL — REV. # 1 (10/08/20)
PUMP VACUUM TEST
To perform the pump vacuum test do the following:
1. Start the engine as outlined in the initial start-up
section, and wait for the pump to begin pumping.
2. Check and make sure that there are no air leaks
between the vacuum tester and the inlet port on
the pump (Figure 22). If air leaks are present reseat
vacuum tester.
3. Run the pump for a few minutes while monitoring the
vacuum gauge. If the gauge indicates a reading
between -25 and -20 in. Hg. (inches of mercury) then
it can be assumed that the pump is working correctly.
4. If the vacuum tester gauge indicates a reading below
-20 in. Hg, it can then be assumed that the pump is
not functioning correctly, and corrective action needs
to be taken.
5. To test the flapper valve, shut down the engine. The
vacuum tester should remain attached to the pump
suction inlet port by vacuum. This indicates the pump's
flapper valve is seating properly to hold water in the
suction hose when the engine is stopped.This prevents
backflow and allows for faster priming when the engine
is restarted.
NOTICE
25 in. Hg (inches of mercury) translates into 25 feet of
lift at sea level.
MAINTENANCE (PUMP)
FLAPPER VALVE REPLACEMENT
1. Remove the two bolts that secure the suction port
chamber Figure 21) to the pump well. Remove
suction port chamber. Replace valves as required and
reassemble.
Figure 21. Flapper Valve Replacement
2. Remove the two bolts that secure the discharge port to
the pump well. Remove discharge port plate.Replace
valves as required and reassemble.

MQD2HA/3HA DIAPHRAGM PUMP • OPERATION MANUAL — REV. # 1 (10/08/20) — PAGE 19
MAINTENANCE (PUMP)
Figure 22. Pump Vacuum Tester
GREASE
CONNECTING
ROD BEARING
MONTHLY

PAGE 20 — MQD2HA/3HA DIAPHRAGM PUMP • OPERATION MANUAL — REV. # 1 (10/08/20)
MAINTENANCE (PUMP)
ROTATION OF SUCTION AND DISCHARGE PORTS
In some applications, it may be preferable to have suction/
discharge ports rotated 90° (Figure 23) to be in-line with
the pump wheels. Perform the following procedure to rotate
ports:
1. Remove the four hex head cap screws, hex nuts, flat
washers and lock washers from the pump base.
2. Push pump well downwards to separate from pump
base.
3. Rotate pump well 90° clockwise so that driver is
positioned over top of discharge plate.
4. Align pump well, pump base, and diaphragm with
each other. Once all components have been properly
aligned, reinstall the four hex head cap screws, hex
nuts, flat and lock washers and tighten securely.
Figure 23. Suction/Discharge Port Rotation
CLEARING A JAM
If large solids or an accumulation of sand, silt or other
sediment gather and become lodged in the pump well, the
plunger arm may be prevented from making a normal full
stroke. This action may cause the pump to stall, the crank
to slip on the output shaft, and ultimately cause damage
to the plunger arm.
Similarly, large damaging solids and debris may build in
the pump well and if not removed, may cause extreme
damage to the plunger arm and pump casing. If a jam
or suspected debris build-up occurs, the pump must be
thoroughly cleaned as described in the “Stalled/Stopped/
Damaging Debris” Section.
HEX HD.
BOLT
FLAT
WASHER
PUMP
BASE
STALLED/STOPPED/DAMAGING DEBRIS
If pump has stalled, stopped, or has been engaged in
moving heavy debris laden fluids, perform the following
procedure:
1. Remove the four hex head cap screws, hex nuts, flat
washers and lock washers from the pump base.
2. Push pump well downwards (Figure 24) to separate
from pump base.
3. Clean and remove all dirt and debris from pump well.
4. Align pump well, pump base, and diaphragm with
each other. Once all components have been properly
aligned, reinstall the four hex head cap screws, hex
nuts, flat and lock washers and tighten securely.
Figure 24. Pump Well (Clean-out)
CAUTION
During the course of pumping operations that include
heavy debris laden fluids, the pump well must be
checked for build-up of rocks, silt, sand and general
de-bris. Failure to clean out the pump cavity (well) could
result in damage to the plunger arm, and pump casing.
HEX HD.
BOLT
FLAT
WASHER
WARNING
Pump jamming with an over-torqued lock screw
(plunger arm) may cause internal damage. Under
torquing may allow the output shaft to spin and wear
parts prematurely causing replacement.