MULTIQUIP QP303B User manual

OPERATION MANUAL
THIS MANUAL MUST ACCOMPANY THE EQUIPMENT AT ALL TIMES.
MODEL
QP303B
CENTRIFUGAL PUMP
(VANGUARD 160 5.0 HP GASOLINE ENGINE)
Revision #0 (05/15/23)
To nd the latest revision of this publication or
associated parts manual, visit our website at:
www.multiquip.com

PAGE 2 — QP303B CENTRIFUGAL PUMP • OPERATION MANUAL — REV. #0 (05/15/23)
PROPOSITION 65 WARNING

QP303B CENTRIFUGAL PUMP • OPERATION MANUAL — REV. #0 (05/15/23)— PAGE 3
TABLE OF CONTENTS
QP303B Centrifugal Pump
Proposition 65 Warning ........................................... 2
Table of Contents..................................................... 3
Safety Information ............................................... 4–8
Specications .................................................... 9–10
General Information................................................11
Components (Pump) ....................................... 12–13
Components (Engine)............................................ 14
Inspection .............................................................. 15
Setup ..................................................................... 16
Operation......................................................... 17–19
Maintenance (Engine) ..................................... 20–22
Maintenance (Pump) ....................................... 24–26
Troubleshooting (Engine) ...................................... 27
Troubleshooting (Pump) ........................................ 28
NOTICE
Specications are subject to change without notice.

PAGE 4 — QP303B CENTRIFUGAL PUMP • OPERATION MANUAL — REV. #0 (05/15/23)
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 speci cally 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.

QP303B CENTRIFUGAL PUMP • OPERATION MANUAL — REV. #0 (05/15/23)— PAGE 5
SAFETY INFORMATION
GENERAL SAFETY
CAUTION

NEVER operate this equipment without proper protective
clothing, shatterproof glasses, respiratory protection,
hearing protection, steel-toed boots or other protective
devices required by the job or city and state regulations.

NEVER operate this equipment when not
feeling well due to fatigue, illness or when
on medication.

NEVER operate this equipment under the in uence of
drugs or alcohol.
NOTICE

This equipment should only be operated by trained and
quali ed personnel 18 years of age and older.

Whenever necessary, replace nameplate, operation and
safety decals when they become dif cult to read.

Manufacturer does not assume responsibility for any
accident due to equipment modi cations. Unauthorized
equipment modi cation 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 the user may result.

ALWAYS know the location of the nearest
 re extinguisher.

ALWAYS know the location of the nearest
 rst 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  re department.
This information will be invaluable in the case of an
emergency.
PUMP SAFETY
DANGER
NEVER
pump volatile, explosive,  ammable or low  ash
point  uids. These  uids could ignite or explode.

The engine fuel exhaust gases contain poisonous carbon
monoxide. This gas is colorless and odorless, and can
cause death if inhaled.

The engine of this equipment requires an adequate free
 ow of cooling air. NEVER
operate this equipment in any
enclosed or narrow area
where free  ow of the air is
restricted. If the air  ow is
restricted it will cause injury
to people and property and
serious damage to the
equipment or engine.
NEVER operate the equipment in an
explosive atmosphere or near combustible
materials. An explosion or  re could result
causing severe bodily harm or even
death.
WARNING
NEVER
pump corrosive chemicals or water containing
toxic substances. These  uids could create serious
health and environmental hazards. Contact local
authorities for assistance.
NEVER open the priming plug when the
pump is hot. Hot water inside could be
pressurized much like the radiator of an
automobile. Allow the pump to cool to
the touch before loosening the plug. The
possibility exists of scalding, resulting in
severe bodily harm.
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.
DANGEROUS
GAS FUMES

PAGE 6 — QP303B CENTRIFUGAL PUMP • OPERATION MANUAL — REV. #0 (05/15/23)
SAFETY INFORMATION
CAUTION

NEVER lubricate components or attempt service on a
running machine.

NEVER block or restrict  ow from a discharge hose.
Remove kinks from the discharge line before starting
the pump. Operation with a blocked discharge line can
cause water inside the pump to overheat.
NOTICE

ALWAYS  ll the pump casing with water before starting
the engine. Failure to maintain water inside the pump
housing will cause severe damage to the pump and
mechanical seal.

In winter, drain water from the pump housing to prevent
freezing.

NEVER start the pump with the clean-out cover removed.
The rotating impeller inside the pump can cut or sever
objects caught in it. Before starting the pump, check that
the clean-out cover is securely fastened.

ALWAYS keep the machine in proper running condition.

ALWAYS ensure the pump is on level ground before use.

Fix damage to the 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.
ENGINE SAFETY
WARNING

NEVER operate the engine with heat shields or guards
removed.

DO NOT remove the engine oil drain plug
while the engine is hot. Hot oil will gush
out of the oil tank and severely scald any
persons in the general area of the pump.
CAUTION

NEVER touch the hot exhaust manifold,
muf er or cylinder. Allow these parts to cool
before servicing the equipment.
NOTICE
NEVER
run the engine without an air  lter or with a dirty
air  lter. Severe engine damage may occur. Service the
air  lter frequently to prevent engine malfunction.
NEVER tamper with the factory settings of
the engine or engine governor. Damage
to the engine or equipment can result
if operating in speed ranges above the
maximum allowable.
FUEL SAFETY
DANGER
DO NOT
add fuel to equipment if it is placed inside a
truck bed with plastic liner. Possibility exists of explosion
or  re due to static electricity.
DO NOT
start the engine near spilled fuel or combustible
 uids. Fuel is extremely  ammable and its vapors can
cause an explosion if ignited.
ALWAYS
refuel in a well-ventilated area, away from
sparks and open  ames.
ALWAYS
use extreme caution when working with
 ammable liquids.
DO NOT  ll the fuel tank while the engine is running
or hot.
DO NOT
over ll the tank, as spilled fuel can ignite if it
comes into contact with hot engine parts or sparks from
the ignition system.

QP303B CENTRIFUGAL PUMP • OPERATION MANUAL — REV. #0 (05/15/23)— PAGE 7
SAFETY INFORMATION
Store fuel in appropriate containers, in well-ventilated
areas and away from sparks and  ames.

NEVER use fuel as a cleaning agent.

DO NOT smoke around or near the
equipment. Fire or explosion could result
from fuel vapors or if fuel is spilled on a
hot engine.
BATTERY SAFETY (ELECTRIC START ONLY)
DANGER

DO NOT drop the battery. There is a possibility that the
battery will explode.

DO NOT expose the battery to open  ames,
sparks, cigarettes, etc. The battery contains
combustible gases and liquids. If these
gases or liquids come into contact with a
 ame or spark, an explosion could occur.
WARNING

ALWAYS wear safety glasses when
handling the battery to avoid eye irritation.
The battery contains acids that can cause
injury to the eyes and skin.

Use well-insulated gloves when picking up
the battery.

ALWAYS keep the battery charged. If the battery is not
charged, combustible gas will build up.

DO NOT charge the battery if frozen. Battery can
explode. When frozen, warm the battery to at least
61°F (16°C).

ALWAYS recharge the battery in a well-ventilated
environment to avoid the risk of a dangerous concentration
of combustible gases.

If the battery liquid (dilute sulfuric acid)
comes into contact with clothing or skin,
rinse skin or clothing immediately with
plenty of water.

If the battery liquid (dilute sulfuric acid) comes into
contact with eyes, rinse eyes immediately with plenty
of water and contact the nearest doctor or hospital to
seek medical attention.
CAUTION
ALWAYS disconnect the
NEGATIVE battery terminal
before performing service on the equipment.
ALWAYS
keep battery cables in good working condition.
Repair or replace all worn cables.
TRANSPORTING SAFETY
CAUTION
NEVER
allow any person or animal to stand underneath
the equipment while lifting.
NOTICE

Before lifting, make sure the equipment parts (hook and
vibration insulator) are not damaged and screws are not
loose or missing.

Always make sure the crane or lifting device has
been properly secured to the lifting bail (hook) of the
equipment.
ALWAYS shut down the engine before transporting.
NEVER lift the equipment while the engine is running.

Tighten the fuel tank cap securely and close the fuel
cock to prevent fuel from spilling.
Use adequate lifting cable (wire or rope) of suf cient
strength.

Use a one-point suspension hook and lift straight
upwards.
DO NOT lift the machine to unnecessary heights.

PAGE 8 — QP303B CENTRIFUGAL PUMP • OPERATION MANUAL — REV. #0 (05/15/23)
ALWAYS tie down equipment during transport by
securing the equipment with rope.
ENVIRONMENTAL SAFETY/DECOMMISSIONING
NOTICE
Decommissioning is a controlled process used to safely
retire a piece of equipment that is no longer serviceable.
If the equipment poses an unacceptable and unrepairable
safety risk due to wear or damage or is no longer cost
effective to maintain (beyond life-cycle reliability) and is to
be decommissioned (demolition and dismantlement), be
sure to follow the rules below.

DO NOT pour waste or oil directly onto the ground, down
a drain or into any water source.

Contact your country’s Department of
Public Works or a recycling agency in your
area and arrange for proper disposal of
any electrical components, waste or oil
associated with this equipment.

When the life cycle of this equipment is over, remove
the battery and bring it to an appropriate facility for lead
reclamation. Use safety precautions when handling
batteries that contain sulfuric acid.

When the life cycle of this equipment is over, it is
recommended that the trowel frame and all other metal
parts be sent to a recycling center.
Metal recycling involves the collection of metal from
discarded products and its transformation into raw materials
to use in manufacturing a new product.
Recyclers and manufacturers alike promote the process of
recycling metal. Using a metal-recycling center promotes
energy cost savings.
EMISSIONS INFORMATION
NOTICE
The gasoline engine used in this equipment has been
designed to reduce harmful levels of carbon monoxide
(CO), hydrocarbons (HC) and nitrogen oxides (NOx)
contained in gasoline exhaust emissions.
This engine has been certi ed to meet US EPA evaporative
emissions requirements in the installed con guration.
Attempts to modify or make adjustments to the engine
emission system by unauthorized personnel without proper
training could damage the equipment or create an unsafe
condition.
Additionally, modifying the fuel system may adversely affect
evaporative emissions, resulting in  nes or other penalties.
Emission Control Label
The emission control label is an integral part of the emission
system and is strictly controlled by regulation(s).
The label must remain with the engine for its entire life.
If a replacement emission label is needed, please contact
your authorized engine distributor.
SAFETY INFORMATION

QP303B CENTRIFUGAL PUMP • OPERATION MANUAL — REV. #0 (05/15/23)— PAGE 9
SPECIFICATIONS
Figure 1. QP303B Dimensions
Table 1. Pump Specications
Model QP303B
Type Self-priming, centrifugal pump
Suction Size 3.0 in. (76 mm)
Discharge Size 3.0 in. (76 mm)
Maximum Pumping Capacity 267 gallons/minute (1,011 liters/minute)
Maximum Suction Lift 25 ft. (7.6 m)
Maximum Head 105 ft. (32.0 m)
Dry Net Weight 79.4 lb. (36 kg)
A
B C
Table 2. QP303B Dimensions
Reference
Letter
Dimension
in. (mm)
A 18.11 (460)
B16.30 (414)
C 20.71 (526)

PAGE 10 — QP303B CENTRIFUGAL PUMP • OPERATION MANUAL — REV. #0 (05/15/23)
SPECIFICATIONS
Figure 2. QP303B Performance Curve
Table 3. Engine Specications
Model Vanguard 160 10V3
Type Air-cooled, four-stroke, single-cylinder, OHV,
horizontal shaft, gasoline engine
Bore × Stroke 2.44 in. × 2.2 in. (62 mm × 56 mm)
Displacement 169 cc (10.31 cu. in.)
Gross Power 5.0 hp (3.7 kW) @ 3,600 rpm
Fuel Tank Capacity Approx. 0.82 gallons (3.1 liters)
Fuel Type Unleaded automobile gasoline
Lube Oil Capacity 0.63 quarts (0.6 liters)
Starting Method Recoil start
Dimensions
(L × W × H)
12.68 × 14.42 × 14.22 in.
(322 × 366 × 361 mm)
Dry Net Weight 39.5 lb. (17.9 kg)
0
10
20
30
40
50
60
70
80
90
100
110
0 50 100 150 200 250 30
0
Suction Line : 3 inch Discharge Line : 3 inch
TOTAL HEAD
FEET
.
METERS
1000
5
10
15
20
25
30
0500
32
3.3 FT
23.3 FT
16.7 FT
10 FT
U.S. GALLONS
PER MINUTE
LITERS
PER MINUTE

QP303B CENTRIFUGAL PUMP • OPERATION MANUAL — REV. #0 (05/15/23)— PAGE 11
ELEVATION
The elevation at which the pump is operated impacts its
performance. Due to decreased atmospheric pressure at
higher altitudes, the pump’s priming ability is reduced as
elevation increases.
Pumps generally lose one foot of priming ability for every
1,000 feet (305 meters) of elevation above sea level.
For example, in Flagstaff, Arizona, where the elevation is
approximately 7,000 feet (2,134 meters) above sea level, a
pump with a suction lift of 25 feet (7.6 meters) at sea level
will have a suction lift of only 18 feet (5.5 meters).
Table 4 shows the difference in suction lift at various
elevations.
Table 5 shows the loss of performance as elevation
increases.
ACCESSORIES
Multiquip offers a complete line of ttings, hoses, and
couplers for various pump applications. Contact the
Multiquip Parts Department for more information.
Table 4. Suction Lift At Various Elevations
Altitude In Feet
(Meters) Suction Lift In Feet (Meters)
Sea Level 10 (3.0) 15 (4.6) 20 (6.1) 25 (7.6)
2,000 (609.6) 8.8 (2.7) 13.2 (4.0) 17.6 (5.4) 22 (6.7)
4,000 (1,219.2) 7.8 (2.4) 11.7 (3.6) 15.6 (4.8) 19.5 (5.9)
6,000 (1,828.8) 6.9 (2.1) 10.4 (3.2) 13.8 (4.2) 17.3 (5.3)
8,000 (2,438.4) 6.2 (1.9) 9.3 (2.8) 12.4 (3.8) 15.5 (4.7)
10,000 (3,048) 5.7 (1.7) 8.6 (2.6) 11.4 (3.5) 14.3 (4.4)
Table 5. Performance Loss At Various Elevations
Altitude In Feet
(Meters) Discharge Flow Discharge Head
Sea Level 100% 100%
2,000 (609.6) 97% 95%
4,000 (1,219.2) 95% 91%
6,000 (1,828.8) 93% 87%
8,000 (2,438.4) 91% 83%
10,000 (3,048) 88% 78%
GENERAL INFORMATION
INTRODUCTION
The QP303B centrifugal pump is a self-priming pump
designed to handle all types of clear-water applications. It
is ideal for residential use such as dewatering basements
and swimming pools.
The pump’s suction and discharge ports are three
inches (76 mm) in diameter, enabling a discharge rate of
approximately 267 gallons per minute (gpm) / 1,011 liters
per minute (lpm).
ENGINE
The QP303B is powered by a 5.0-horsepower, air-cooled,
four-stroke, single-cylinder, Vanguard 160 gasoline engine.
CENTRIFUGAL PUMPS
Standard centrifugal pumps provide an economical
choice for general purpose dewatering. These types of
pumps should only be used in clear-water applications
(agricultural, industrial, residential), as they have a limited
solid-handling capability of only 10% by volume.
PUMP PRIMING
The pump is self-priming, therefore the pump casing
must be lled with water before the pump is operated.
The engine drives a rotating impeller that creates a partial
vacuum (low pressure) within the pump. The reduced
internal air pressure causes water to ow continuously into
the pump through the suction line, and the centrifugal force
of the impeller expels the water from the pump through the
discharge ports.
NEVER attempt to operate the pump without lling the
casing with water rst.
SUCTION LIFT
The QP303B centrifugal pump has a maximum suction lift
of 25 feet (7.6 meters) at sea level. To obtain the optimum
suction lift, ALWAYS place the pump as close to the water
as possible and use the shortest possible suction line.

PAGE 12 — QP303B CENTRIFUGAL PUMP • OPERATION MANUAL — REV. #0 (05/15/23)
COMPONENTS (PUMP)
Figure 3 shows a typical QP303B centrifugal pump
application. The main pump components are listed below.
Figure 3. Pump Components
12
3
4
5
5
7
8
5
9
6
NOTICE
This pump is intended for the removal of clean water.

QP303B CENTRIFUGAL PUMP • OPERATION MANUAL — REV. #0 (05/15/23)— PAGE 13
1. Fill Cap — Remove the ll cap to add water to the
pump. The pump casing must be lled with water
prior to operation! After the initial prime, a sufcient
amount of water will be retained in the casing so that
the operator will not need to re-prime later.
2. Discharge Port — Three-inch (76 mm), male,
NPT-threaded discharge port accommodates threaded
hoses or pipes. Make sure hose lays at and is not
kinked. Use only the recommended type of discharge
hose. Contact the Multiquip Parts Department for
ordering information.
3. Engine — A 5.0-horsepower, air-cooled, four-stroke,
single-cylinder, Vanguard 160 gasoline engine. Refer
to the Components (Engine) section of this manual
for more information.
4. Discharge Hose — Discharge hoses are usually
collapsible (thin-walled) hoses. However, if a thin-walled
discharge hose is not available, a rigid suction hose
may be substituted. MAKE SURE hoses lay flat
and remain unkinked. Contact the Multiquip Parts
Department for ordering information.
5. Worm Clamps — Worm clamps secure the hoses to
the inlet and outlet ports on the pump. Use two worm
clamps to secure a hose to the suction port.
6. Drain Plug — Remove the drain plug to drain water
from the pump casing.
7. Suction Port — Three-inch (76 mm), male,
NPT-threaded suction port accommodates threaded
hoses or pipes. Make sure hose lays at and is not
kinked. Use only the recommended type of suction
hose. Contact the Multiquip Parts Department for
ordering information.
8. Suction Hose — Suction hoses are commonly
reinforced with rigid PVC helix and are specically
designed to prevent collapse during operation. Use
recommended suction hoses only. MAKE SURE the
suction hose remains unkinked. Contact the Multiquip
Parts Department for ordering information.
WARNING
NEVER remove the ll cap while the pump is hot.
Pressurized water inside can cause serious injury.
9. Strainer — ALWAYS attach the strainer to the bottom
end of the suction hose to prevent large objects and
debris from entering the pump. Position the strainer so
that it remains completely underwater.
NOTICE
Running the pump for sustained periods with the
strainer above the water surface can damage the pump.
COMPONENTS (PUMP)

PAGE 14 — QP303B CENTRIFUGAL PUMP • OPERATION MANUAL — REV. #0 (05/15/23)
COMPONENTS (ENGINE)
Figure 4. Basic Engine Components
1
23
4
5
6
7
8
9
10
11
9
8
8
INITIAL SERVICING
The engine (Figure 4) must be checked for proper
lubrication and lled with fuel prior to operation. Refer to
the manufacturer’s engine manual for detailed operation
and service instructions.
1. Engine Oil Dipstick — Remove to determine if engine
oil is low.
2. Fuel Filler Cap — Remove to add unleaded gasoline to
the fuel tank. Make sure the cap is tightened securely.
NEVER overll.
3. Fuel Tank — Holds up to 3.2 quarts (3.1 liters) of
unleaded gasoline.
4. Spark Plug — Provides spark to the ignition system.
Set the spark plug gap according to the engine
manufacturer’s instructions, and clean the spark plug
once a week.
5. Throttle Lever — Adjusts engine speed (RPM).
DANGER
NEVER ll the fuel tank while the engine
is running or hot. In the event of a fuel
spill, DO NOT start the engine until all
fuel residue has been wiped up and the
area surrounding the engine is dry. Fuel
is extremely ammable and can ignite if
it comes into contact with hot engine parts
or sparks from the ignition system.
6. Air Cleaner — Prevents dirt and other debris from
entering the fuel system.
7. Mufer — Reduces noise and emissions. DO NOT
touch the mufer while it is hot. Appearance may vary.
8. Oil Filler Cap (3) — Add engine oil through this port
as recommended in Table 6.
9. Oil Drain Bolt (2) — Remove to drain oil from the
engine crankcase.
10. Recoil Starter — Manual starting mechanism. Pull
the starter grip slowly until resistance is felt, then pull
briskly and smoothly to start the engine.
11. Choke Lever — Aids in starting a cold engine or
starting in cold weather conditions. The choke enriches
the fuel mixture.
NOTICE
Operating the engine without an air lter, or with a
damaged or worn air lter in need of replacement, will
allow dirt to enter the engine, causing rapid engine wear.
WARNING
Engine components can generate
extreme heat. To prevent burns, DO NOT
touch these areas while the engine is
running or immediately after operating.
DO NOT operate the engine with the
mufer removed.

QP303B CENTRIFUGAL PUMP • OPERATION MANUAL — REV. #0 (05/15/23)— PAGE 15
INSPECTION
BEFORE STARTING
1. Read the safety instructions at the beginning of this
manual.
2. Clean the pump, particularly the engine cooling air
inlet. Remove all dirt and dust.
3. Inspect the air cleaner for dirt and dust. If the air cleaner
is dirty, replace the lter with a new one as required.
4. Inspect the carburetor for external dirt and dust. Clean
with dry compressed air as needed.
5. Inspect all fastening nuts and bolts for tightness.
ENGINE OIL CHECK
1. Place the pump on secure, level ground with the
engine OFF.
2. Remove the dipstick (Figure 5) from its holder and
wipe it clean.
Figure 5. Engine Oil Dipstick
3. Reinsert the dipstick, then remove it again and check
the oil level shown on the dipstick (Figure 5). The
correct oil level is at the top of the full indicator on the
dipstick.
CAUTION
DO NOT attempt to operate the pump
until the Safety Information, General
Information, and Inspection sections
of this manual have been thoroughly
read and understood.
ADD
ADD
OIL
FULL
LIMIT
DIPSTICK
4. If the oil level is low, remove one of the oil ller caps
(Figure 6) and ll with the recommended oil type
listed in Table 6. DO NOT overll. Maximum engine
oil capacity is 0.63 quarts (0.6 liters).
Figure 6. Oil Filler Caps
FUEL CHECK
Remove the fuel ller cap and inspect the fuel level in
the tank. If fuel is low, replenish with 87 octane or higher
unleaded gasoline. Maximum fuel capacity is 0.82 gallons
(3.1 liters).
OIL FILLER
CAPS (3)
Table 6. Recommended Oil Viscosity Grades
AMBIENT TEMPERATURE
–20
–20 –10 0 10 20 30 40°C–30
0 20 40 60 80 100°F
SAE 30
SAE 5W-30
SAE 10W-30
SAE SYNTHETIC 5W-30
VANGUARD SYNTHETIC 15W-50
DANGER
Motor fuels are highly ammable and
can be dangerous if mishandled. DO NOT
smoke while refueling. DO NOT attempt to
refuel while the engine is running or hot!
WARNING
ALWAYS use a strainer for ltration while refueling.
NEVER top off fuel. ALWAYS wipe up any spilled fuel
immediately.

PAGE 16 — QP303B CENTRIFUGAL PUMP • OPERATION MANUAL — REV. #0 (05/15/23)
SETUP
Pump performance (ow, head, velocity and pressure) is
determined by multiple factors, including operating altitude,
suction lift, the length and diameter of the hoses, friction
loss, the specic gravity and temperature of the uid being
pumped, and total discharge head. Set up the pump as
follows to achieve optimal pump performance.
1. Place the pump on a solid, level operating surface as
close as possible to the water source. The most critical
factor for successful pump operation is the total suction
lift, which should not exceed 25 feet (7.6 meters) at
sea level. See Figure 7.
2. Initialize self-priming of the pump by removing the ll
cap and lling the pump casing with water.
3. Check for water leakage between the pump and the
engine, which may indicate that the seal inside the
pump is worn or damaged. Continued operation of the
pump in this condition is not recommended, and can
cause severe water damage to the engine.
NOTICE
THE PUMP CASING MUST BE FILLED WITH WATER
PRIOR TO OPERATION. Self-priming of the pump
will not take place unless the pump casing is lled
with water.
NOTICE
This pump uses a water-cooled mechanical seal
to prevent water from seeping into the engine. The
passage of water through the pump casing lubricates
the seal and prevents it from overheating. NEVER
operate the pump without water in the casing, as this
can damage the mechanical seal.
4. Connect suitable hoses to the suction and discharge
ports. MAKE SURE the hoses are tightly secured to
their respective ports, have O-rings in place, and are
free of any kinks, cracks, gouges, or holes. Using two
hose clamps to secure the suction hose to the suction
port is recommended.
5. MAKE SURE the strainer is clean and securely
attached to the water end of the suction hose. Position
the strainer so it will remain completely underwater,
but is not buried in any underlying sand or silt.
6. MAKE SURE the discharge hoses lay as straight as
possible and remain unrestricted. Remove any twists,
kinks, or sharp bends which may impede the ow of
water.
NOTICE
Suction and discharge hoses are available from
Multiquip. Contact your local MQ dealer for more
information.
NOTICE
Sustained pump operation with the strainer above the
water surface can damage the pump.
NOTICE
Discharge hoses are usually collapsible (thin-walled)
hoses. However, if thin-walled discharge hoses are
not available, rigid suction hoses may be substituted.
PVC pipe or concrete pipe can also be connected to
the discharge ports.
Figure 7. Pump Setup

QP303B CENTRIFUGAL PUMP • OPERATION MANUAL — REV. #0 (05/15/23)— PAGE 17
OPERATION
DANGER
NEVER operate the pump in a conned
area or enclosed structure that does not
provide an ample free ow of air.
WARNING
NEVER pump ammable uids, corrosive chemicals,
or uids containing toxic substances. These uids can
create potentially dangerous health and environmental
hazards. Contact local authorities for assistance.
CAUTION
DO NOT attempt to operate the pump
until the Safety Information, General
Information, and Inspection sections
of this manual have been thoroughly
read and understood.
CAUTION
ALWAYS wear approved eye and hearing
protection while operating the pump.
NOTICE
NEVER attempt to start the engine unless the pump
has rst been primed with water. Severe damage will
occur to the pump’s mechanical seal if the pump has
not been primed.
STARTING THE ENGINE
1. Move the engine throttle lever (Figure 8) to the IDLE
position (away from the OFF position, about 1/3 of the
way toward the RUN position).
Figure 8. Throttle Lever (Idle)
2. If starting a cold engine, place the engine choke lever
in the CLOSED position (Figure 9).
Figure 9. Choke Lever (Closed)
RUN
IDLE
THROTTLE
LEVER
OFF
OPEN
CHOKE
LEVER
CLOSE

PAGE 18 — QP303B CENTRIFUGAL PUMP • OPERATION MANUAL — REV. #0 (05/15/23)
OPERATION
3. If starting a warm engine, place the engine choke
lever in the OPEN position (Figure 10).
Figure 10. Choke Lever (Open)
4. Slowly pull the starter grip (Figure 11) until resistance
is felt, then pull briskly and smoothly to start the engine.
Gently return the starter grip to its original position.
Figure 11. Starter Grip
5. If the engine has started, slowly return the choke lever
to the OPEN position (Figure 10) as the engine warms.
If the engine has not started, repeat steps 1–5.
6. Run the engine at idle for several minutes and check
for any abnormal conditions such as extreme vibration,
loose components, or uid leaks.
CLOSE
OPEN
CHOKE
LEVER
7. To begin pumping, place the engine throttle lever
(Figure 12) in the RUN position.
Figure 12. Throttle Lever (Run)
RUN
IDLE
THROTTLE
LEVER
WARNING
Water must always be flowing through the pump
casing while the engine is running. Loss of ow may
be the result of a loss of prime, restricted water ow,
or a dead-head situation. Please note that in such a
condition, water in the pump can reach temperatures
of 150–200°F in 15–20 minutes. This can cause
serious burns if this hot water comes into contact with
unprotected skin.
Before touching or opening the ll plug or drain plug,
rst turn off the engine and allow the pump casing to
cool to the touch, then open the pump carefully. Be
cautious of any built-up water pressure.
CAUTION
ALWAYS run the engine at full speed while pumping.

QP303B CENTRIFUGAL PUMP • OPERATION MANUAL — REV. #0 (05/15/23)— PAGE 19
OPERATION
STOPPING THE ENGINE
Normal Shutdown
1. Place the engine throttle lever in the IDLE position
(Figure 13), and run the engine for three minutes at
low speed.
Figure 13. Throttle Lever (Idle)
2. After the engine has cooled, place the engine throttle
lever in the OFF position (Figure 14). This action will
also turn off the engine fuel valve.
Figure 14. Engine Throttle Lever (OFF)
RUN
IDLE
THROTTLE
LEVER
OFF
IDLE
THROTTLE
LEVER
OFF
NOTICE
When transporting the pump, ALWAYS turn off the
engine fuel valve by placing the engine throttle lever
in the OFF position.
Emergency Shutdown
Move the engine throttle lever quickly to the OFF position
(Figure 15).
Figure 15. Emergency Shutdown
OFF
RUN
THROTTLE
LEVER

PAGE 20 — QP303B CENTRIFUGAL PUMP • OPERATION MANUAL — REV. #0 (05/15/23)
ENGINE MAINTENANCE
Perform engine maintenance procedures according to Table 7 below:
Table 7. Engine Maintenance Schedule
Description(3) Operation First 5
Hours
Every 8
Hours or
Daily
Every 100
Hours or
Annually
Every 200
Hours or
Annually
Annually
Every 600
Hours or
3 Years
Engine Oil Check X
Change X X
Fuel System Service X
Area Around
Mufer and
Controls
Clean X
Spark Plug Replace X
Air Intake
Grille Clean X
Exhaust
System Service X
Air Filter Clean X(1)
Replace X
Cooling
System Service X(1)
Valve
Clearance Check X(2)
(1) In dusty conditions or when airborne debris is present, clean more often.
(2) Not required unless engine performance problems are noted.
(3) For commercial use, log hours of operation to determine proper maintenance intervals.
MAINTENANCE (ENGINE)