MULTIQUIP MAYCO LS300GK User manual

OPERATION MANUAL
THIS MANUAL MUST ACCOMPANY THE EQUIPMENT AT ALL TIMES.
Revision #1 (10/14/22)
SERIES
MODEL LS300GK
CONCRETE PUMP
(KUBOTA WG3800-G-E3 GASOLINE ENGINE)
To find the latest revision of this publication or
associated parts manual, visit our website at:
www.multiquip.com

PAGE 2 — MAYCO LS300GK CONCRETE PUMP • OPERATION MANUAL — REV. #1 (10/14/22)
PROPOSITION 65 WARNING

MAYCO LS300GK CONCRETE PUMP • OPERATION MANUAL — REV. #1 (10/14/22) — PAGE 3
Grinding/cutting/drilling of masonry, concrete, metal and
other materials with silica in their composition may give
off dust or mists containing crystalline silica. Silica is a
basic component of sand, quartz, brick clay, granite and
numerous other minerals and rocks. Repeated and/or
substantial inhalation of airborne crystalline silica can
cause serious or fatal respiratory diseases, including
silicosis.Inaddition, California and some other
authorities have listed respirable crystalline silica as a
substance known to cause cancer. When cutting such
materials, always follow the respiratory precautions
mentioned above.
WARNING
Grinding/cutting/drilling of masonry, concrete, metal and
other materials can generate dust, mists and fumes
containing chemicals known to cause serious or fatal
injury or illness, such as respiratory disease, cancer,
birth defects or other reproductive harm. If you are
unfamiliar with the risks associated with the particular
process and/or material being cut or the composition of
the tool being used, review the material safety data
sheet and/or consult your employer, the material
manufacturer/supplier, governmental agencies such as
OSHA and NIOSH and other sources on hazardous
materials. California and some other authorities, for
instance, have published lists of substances known to
cause cancer, reproductive toxicity,or other harmful
effects.
Control dust, mist and fumes at the source where
possible. In this regard use good work practices and
follow the recommendations of the manufacturers or
suppliers, OSHA/NIOSH, and occupational and trade
associations.Water should be used for dust
suppression when wet cutting is feasible. When the
hazards from inhalation of dust, mists and fumes cannot
be eliminated, the operator and any bystanders should
always wear a respirator approved by NIOSH/MSHA for
the materials being used.
WARNING
SILICOSIS WARNING RESPIRATORY HAZARDS
SILICOSIS/RESPIRATORY WARNINGS

PAGE 4 — MAYCO LS300GK CONCRETE PUMP • OPERATION MANUAL — REV. #1 (10/14/22)
TABLE OF CONTENTS
LS300GK Concrete Pump
Proposition 65 Warning ........................................... 2
Silicosis/Respiratory Warnings ................................ 3
Table Of Contents.................................................... 4
Safety Information ............................................. 6–11
Specifications ........................................................ 12
Dimensions............................................................ 13
Important Hand Signals......................................... 14
General Information......................................... 15–21
Pump Components.......................................... 22–25
Digital Control Panel Components .................. 26–27
Engine Components.............................................. 28
Inspection ........................................................ 29–31
Setup ..................................................................... 32
Operation......................................................... 33–38
Maintenance.................................................... 40–53
Trailer Maintenance ......................................... 54–56
Trailer Guidelines............................................. 57–71
Appendix — Concrete Mix Information............ 72–74
Troubleshooting (Pump) .................................. 75–76
Troubleshooting (Engine)................................. 77–78
Troubleshooting (Hydraulic Brakes)....................... 79
Troubleshooting (Electrical) ............................. 80–81
Troubleshooting (Diagnostics) ......................... 82–87
Hydraulic System Locator Diagram ....................... 88
Hydraulic System Diagram .................................... 89
Electrical System Locator Diagram ....................... 90
Electrical System Diagram 1 ................................. 91
Electrical System Diagram 2 ................................. 92
Electrical System Diagram 3 ................................. 93

MAYCO LS300GK CONCRETE PUMP • OPERATION MANUAL — REV. #1 (10/14/22) — PAGE 5
NOTES

PAGE 6 — MAYCO LS300GK CONCRETE PUMP • OPERATION MANUAL — REV. #1 (10/14/22)
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.
OFF
Lethal Exhaust Gas Hazards
Explosive Fuel Hazards
Burn Hazards
Respiratory Hazards
Accidental Starting Hazards
Eye and Hearing Hazards
Pressure Hazards
Symbol Safety Hazard
Rotating Parts Hazards
Hydraulic Fluid Hazards

MAYCO LS300GK CONCRETE PUMP • OPERATION MANUAL — REV. #1 (10/14/22) — PAGE 7
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.

NEVER operate this equipment when not
feeling well due to fatigue, illness, or while
on medication.

NEVER operate this equipment under the influence of
drugs or alcohol.
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 to 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.
PUMP SAFETY
DANGER
NEVER
pump volatile, explosive, flammable or low flash
point fluids. These fluids 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
flow of cooling air. NEVER
operate this equipment in any
enclosed or narrow area
where free flow of the air is
restricted. If the air flow 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 fire could result causing severe
bodily harm or even death.
WARNING
NEVER
pump corrosive chemicals or water containing
toxic substances. These fluids could create serious
health and environmental hazards. Contact local
authorities for assistance.
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 8 — MAYCO LS300GK CONCRETE PUMP • OPERATION MANUAL — REV. #1 (10/14/22)
SAFETY INFORMATION
CAUTION

NEVER lubricate components or attempt service on a
running machine.

NEVER block or restrict flow from discharge hose.
Remove kinks from discharge line before starting the
pump.

DO NOT operate this equipment unless the hopper grate,
guards, and safety devices are attached and bolted in
place.

CAUTION must be exercised while servicing this
equipment. Rotating and moving parts can cause injury
if contacted.

Keep hands out of the hopper when the engine is
running.
NOTICE

In winter, drain water and oil from the lubrication box to
prevent freezing.

ALWAYS be sure the operator is familiar with proper
safety precautions and operation techniques before
using the pump.

Keep all inexperienced and unauthorized people away
from the equipment at all times.

Before start-up, check the hopper and remove all foreign
matter and debris.

DO NOT use worn or damaged hose couplings. Inspect
all hoses and couplings for wear. Replace any worn or
defective hose or couplings immediately.

Unauthorized equipment modifications will void all
warranties.

Check all fasteners periodically for tightness. Also check
towing tongue bolt, lock nut ,and wheel lug nuts for wear.

Test the pump’s emergency stop switch. The purpose
of this test is to shut down the engine in the event of an
emergency.

Refer to the Kubota engine owner’s manual for engine
technical questions or information recommended by
Multiquip for this equipment. Damage to the equipment
and or injury to user may result.
ALWAYS remove the ignition key when leaving the pump
unattended.
ALWAYS
block the wheels on the unit when using on
a slope.
ALWAYS
use properly rated hoses and clamps —
1,500 psi or higher.
ALWAYS
allow the pump a proper amount of time to
cool before servicing.
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
DO NOT
place hands or fingers inside the engine
compartment when the engine is running.
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,
muffler, or cylinder. Allow these parts to
cool before servicing equipment.
NOTICE
NEVER
run the engine without an air filter or with a dirty
air filter. Severe engine damage may occur. Service the
air filter 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.

MAYCO LS300GK CONCRETE PUMP • OPERATION MANUAL — REV. #1 (10/14/22) — PAGE 9
SAFETY INFORMATION
FUEL SAFETY
DANGER

DO NOT start the engine near spilled fuel or combustible
fluids. Fuel is extremely flammable and its vapors can
cause an explosion if ignited.

ALWAYS refuel in a well-ventilated area, away from
sparks and open flames.

ALWAYS use extreme caution when working with
flammable liquids.

DO NOT fill the fuel tank while the engine is running
or hot.

DO NOT overfill the fuel tank, as spilled fuel can ignite
if it comes into contact with hot engine parts or sparks
from the ignition system.

Store fuel in appropriate containers, in well-ventilated
areas and away from sparks and flames.

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.

DO NOT overfill the fuel tank. Tighten the fuel cap until
it clicks.
BATTERY SAFETY
DANGER
DO NOT
drop the battery. There is a possibility that the
battery will explode.
DO NOT expose the battery to open flames,
sparks, cigarettes, etc.The battery contains
combustible gases and liquids. If these
gases or liquids come into contact with a
flame 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. The 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.

PAGE 10 — MAYCO LS300GK CONCRETE PUMP • OPERATION MANUAL — REV. #1 (10/14/22)
SAFETY INFORMATION
TRANSPORTING SAFETY
NOTICE

ALWAYS shut down the engine before transporting.

Tighten the fuel tank cap until it clicks to prevent fuel
from spilling.

DO NOT lift the machine.

ALWAYS tie down equipment during transport by
securing the equipment with straps, rope, or chains.
TOWING SAFETY
CAUTION

Check with your local county or state safety
towing regulations, in addition to meeting
Department of Transportation (DOT)
SafetyTowing Regulations,before towing
your generator.

In order to reduce the possibility of an accident while
transporting your concrete pump on public roads,
ALWAYS make sure the trailer that supports the pump
and the towing vehicle are mechanically sound and in
good operating condition.

ALWAYS shut down the engine before transporting.

Make sure the hitch and coupling of the towing vehicle
are rated equal to or greater than the trailer gross vehicle
weight rating.

ALWAYS inspect the hitch and coupling for wear. NEVER
tow a trailer with defective hitches, couplings, chains, etc.

Check the tire air pressure on both towing vehicle and
trailer. Trailer tires should be inflated to 80 psi cold.
Also check the tire tread wear on both vehicles.

ALWAYS make sure the trailer is equipped with a safety
chain.

ALWAYS properly attach the trailer’s safety chains to
the towing vehicle.
ALWAYS make sure the vehicle and trailer directional,
backup, brake, and trailer lights are connected and
working properly.
DOT requirements include the following:
• Connect and test electric brake operation.
• Secure portable power cables in cable tray with tie
wraps.
The maximum speed for highway towing is 55 MPH
unless
posted otherwise. Recommended off-road towing is not to
exceed 15 MPH
or less depending on the type of terrain.

Avoid sudden stops and starts.This can cause skidding
or jack-knifing. Smooth, gradual starts and stops will
improve towing.
Avoid sharp turns to prevent rolling.

Trailer should be adjusted to a level position at all times
when towing.

Raise and lock the trailer wheel stand in the up position
when towing.
Place chock blocks
underneath the wheels to prevent
rolling while parked.
Place support blocks
underneath the trailer’s bumper
to prevent tipping while parked.

Use the trailer’s swivel jack to adjust the trailer height to
a level position while parked.
DO NOT
tow the machine with concrete inside the
hopper.

MAYCO LS300GK CONCRETE PUMP • OPERATION MANUAL — REV. #1 (10/14/22) — PAGE 11
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 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 diesel exhaust emissions.
This engine has been certified to meet US EPA evaporative
emissions requirements in the installed configuration.
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 fines or other penalties.
Emission Control Label
The emission control label is an integral part of the emission
system and is strictly controlled by regulations.
The label must remain with the engine for its entire life.
If a replacement emission label is needed, please contact
your authorized Kubota engine distributor.
SAFETY INFORMATION

PAGE 12 — MAYCO LS300GK CONCRETE PUMP • OPERATION MANUAL — REV. #1 (10/14/22)
SPECIFICATIONS
Table 13. Pump Specifications
Model LS300GK
Pumping Rate Up to 30 cu. yd. per hour*
Pumping Method Reciprocating piston
Maximum Aggregate Size 1-1/2 in. minus (38 mm)
Piston Face Pressure 800 psi (55.16 bar)
Cylinder Lubrication Box Capacity 4.4 gallons (16.6 liters)
Hydraulic Fluid Capacity 33 gallons (125 liters)
Hydraulic Fluid Type Shell Tellus 46
Fuel Tank Capacity 16 gallons (61 liters)
Hopper Capacity 10 cu. ft.
Material Hose Diameter 3 in. / 4 in. / 5 in. (76 mm / 102 mm / 127 mm)
Weight (with fluids) 4,486 lb. (2,035 kg)
Tire Size ST 225/75 R15
Options Wireless remote control, hopper screen vibrator
*Volume output will vary depending on mix design, slump, line size used, and job site conditions.
Table 14. Engine Specifications
Model Kubota WG3800-G-E3
Type Vertical, water-cooled, 4-cycle
No. of Cylinders 4
Bore × Stroke 3.93 in. × 4.72 in. (100 mm × 120 mm)
Rated Output 85 hp (63.3 kW) @ 2,600 rpm
Displacement 229.9 cu. in. (3.769 liters)
Starting Electric 12V × 2.5 kW
Lube Oil Capacity with Filter 3.22 gal. (12.2 liters)
Coolant Capacity with Radiator 2.38 gal. (9.0 liters)
Fuel Type Unleaded gasoline
Battery 12V BCI Group 24
Weight Dry 635 lb. (288 kg)
Dimensions L × W × H 27.6 in. × 22.8 in. × 31.5 in. (700 mm × 579 mm × 799 mm)

MAYCO LS300GK CONCRETE PUMP • OPERATION MANUAL — REV. #1 (10/14/22) — PAGE 13
Figure 1. Dimensions
D
C
A
E
B
Table 1. Pump Dimensions
Reference
Letter
Dimensions
in. (mm)
A 158 (4,013)
B 44.0 (1,118)
C 75.5 (1,917)
D 21.5 (546)
E 63.5 (1,613)
DIMENSIONS

PAGE 14 — MAYCO LS300GK CONCRETE PUMP • OPERATION MANUAL — REV. #1 (10/14/22)
IMPORTANT HAND SIGNALS
Figure 2. Operational Hand Signals
CHUTE UP CHUTE DOWN STOP START PUMP
SPEED UP
SLOW PUMP
DOWN
STOP PUMP LITTLE BIT ADD WATER
4-GALLONS
ALL DONE
CLEAN-UP
DRIVE IN BACK UP
PULL FORWARD BACK IN

MAYCO LS300GK CONCRETE PUMP • OPERATION MANUAL — REV. #1 (10/14/22) — PAGE 15
GENERAL INFORMATION
CONCRETE MIX DESIGN
Mix design is most important to achieve maximum
pumpability. Pumpability is affected by, among other
factors, the type and gradation of aggregate used. Natural
aggregates make a more workable mix and pump more
readily than crushed aggregates. A blend of natural and
crushed aggregates will produce a workable mix. The
type and gradation of aggregates is equally important
for workability as the size and percentage of coarse
aggregates in the mix.
The term “aggregates” describes all of the solid materials,
from the largest rock to the smallest grain of sand,
contained in the concrete mix.
Concrete mixes with a consistency as dry as one-inch
slump and as wet as ten-inch slump have been pumped;
but for maximum efficiency from the pump, a slump ranging
from two to six inches will produce a more workable mix
than one that contains more or less water.
The principle of concrete pumping is based on
self-lubrication. As it moves through the transfer line,
the concrete takes the shape of a plastic cylinder. It is
forced through the transfer line on a film of mortar that is
self-troweled to the service of the transfer line around its
full periphery by the slug of concrete itself.
A slump rating should be used with discretion; it is not
always a real indication of the pumpability of the mix. The
concrete may be workable in the sense that it will readily
flow into place, but the same mix may not respond to
pressure.
Overly wet mixes tend to separate. In addition to affecting
the strength and quality of the concrete, the delivery
system will not tolerate separation. Overly dry mixes are
similarly unsatisfactory if they lack plasticity and tend to be
crumbly. To be properly pumped, the mix must be able to
continuously coat the inside of the line with a lubricating
seal of mortar.
There are four ways in which this seal can be lost:
1. By pumping excessively wet mixes which do not have
enough cohesion to hold together.
2. By pumping harsh, undersanded concrete with poorly
graded aggregates which can jam together when the
pressure becomes too great for the insufficient amount
of sand to hold the aggregates apart.
3. By getting a rock pocket, such as mixer tailings, into the
pump valve. This rock pocket will have an insufficient
coating of mortar and the mix will not be plastic enough
to allow the valve to operate or the mix to move in the line.
4. Through excessive bleeding. If the mix is short or fine,
but the sand is otherwise fairly well graded, bleeding
will not normally create any problems as long as the
pump continues operation. But, if the pump is shut
down, bleeding can result in a loss of lubrication and
blocked, erratic flow.
The above are bad concrete practices, regardless of
how the mix is to be placed. But these points do show
that special mixes are not always needed, within limits,
for pumping concrete. Good aggregate gradation is most
important to pump concrete the maximum distance.
The use of admixtures can have a beneficial effect on
pumpability. Most of the dispersing agents will fatten,
retard bleeding, and increase workability.Thus, the average
concrete can be pumped for appreciably longer distances.
Air entraining agents will also improve workability, although
they cannot be used as a substitute for good gradation of
the aggregate.
Pumping will not appreciably affect the final air content of
the mix. High-early cement tends to give a more readily
pumpable mix with superior water-retaining qualities.
However, if delays are likely to occur, extra care must be
exercised due to the faster setting time over regular cement.
The Mayco LS300GK will pump a wide variety of concrete
pump mixes, but there are guidelines that must be followed.
Use this information in conjunction with the Operation
section of this manual.

PAGE 16 — MAYCO LS300GK CONCRETE PUMP • OPERATION MANUAL — REV. #1 (10/14/22)
REGIONAL DIFFERENCES
Concrete is made by mixing locally available rock and sand
with cement and water. For this reason there are great
differences in the pumpability of concrete from one region
of the country to another.
It is impossible to define a specific mix for each region
that the concrete pump will be working in. Therefore, the
mixes listed in the Appendix — Concrete Mix Information
section of this manual will provide a basic guideline for
establishing the proper mix design for your area.
Use this information to specify your requirements to your
local ready-mix batch plant, contractor, and civil engineer.
It may take minor adjustments to make a mix pumpable,
so you should explain your needs.
The elements that have to be controlled and consistently
maintained by the batch plant are:
1. The sizing and mix percentage of rocks, gap graded
from the largest down through the smallest sizes.
2. Sand with a sieve analysis that has the proper
percentage of fines, ASTM C33 spec.
3. Sufficient cement to produce the required design
strength of the concrete and provide the lubricating
binder to pump the concrete through the delivery
system.
Use a minimum of:
500 pounds of cement per cubic yard for 2,500 psi
concrete after 28 days.
530 pounds of cement per cubic yard for 3,000 psi
concrete after 28 days.
600 pounds of cement per cubic yard for 4,000 psi
concrete after 28 days.
4. Admixture pump-aid if necessary.
5. The proper amount of water to make a workable slump
and plasticize the mix.
GENERAL INFORMATION
In addition, this Mayco concrete pump can be used to pump
a large aggregate hard rock as follows:
Pea rock (1/2" minus) pump with mixes being as low as
30% rock and 70% sand. (Refer to the Maintenance
section for recommendations on cleaning the pump.)
Shortening pea rock when used with an air compressor
and nozzle.
“Mud jacking,” high-pressure grouting.
PUMPING INFORMATION
Remixtures
Remixtures are designed into the concrete mix by the
ready-mix company or an architectural engineering
company.This section lists common admixtures and a brief
explanation of their functions:
1. Pozzolith 300 (or Equivalent) — Acts as a water
retarder and a lubricant. On lean mixes, long pushes,
stiff mixes, and vertical pushes, Pozzolith 300R helps
pumpability.
2. MBVR — Air entraining, acts as a lubricant.
3. Calcium Chloride — Commonly referred to as CC,
is used as an accelerator. When pumping a load with
calcium chloride, it is recommended that you wash out
if the waiting time between delivery trucks becomes
too long.
4. Super Plasticizer — Acts as an accelerator. The
concrete will look very wet after the super plasticizer
is added, but will begin to set up very fast. Wash out
immediately if you do not have a truck waiting. Super
plasticizers are used mainly on commercial jobs.
5. Red Label — Acts as a water retarder and an
accelerator. Red label will be used mainly on
commercial jobs.
6. Fly Ash — Is used to help increase the strength of the
concrete and decrease the cement content per yard.
This is one of the most common admixtures used.
NOTICE
All admixtures will be shown on the ready-mix concrete
ticket.Before starting the pumping job, ask the driver of the
ready-mix truck to see the concrete ticket, then note the
admixtures that exist and take the proper action.

MAYCO LS300GK CONCRETE PUMP • OPERATION MANUAL — REV. #1 (10/14/22) — PAGE 17
GENERAL INFORMATION
Downhill Pumping
Downhill pumping can be a difficult procedure on some
jobs.The slurry procedure would be the same as explained
under Priming the Pump with Slurry Mixture in the
Operation section of this manual. It is suggested that a
sponge approximately 2" × 4" × 6" be placed in the hose
before the start of pumping.
Wet the sponge before placing it in the hose to keep the
slurry from running too far ahead of the concrete, which
will reduce the possibility of separation. When the pump is
stopped, the material can flow slowly down, due to gravity,
and cause the hose to collapse.
When pumping is resumed, you can expect blockage at
the point of hose collapse.To prevent this from happening,
the hose can be “kinked off” at the discharge end when the
pump is stopped to prevent the gravity flow of the material
in the hose.
The use of stiffer mixes when pumping downhill will
decrease gravity flow of the material in the hose and
will assure a smoother operation between the cam roller
bearing and cam plate. As with any job, make sure that
the hose and the couplings are in good, working condition.
Vertical Pumping
When pumping vertically up the side of a building (above
40 feet), we would recommend the installation of steel pipe
securely fastened at intervals as necessary to support the
pipe. Ninety-degree, long-radius pipe sweeps should be
installed at the top and bottom of the steel line.
Use a 25-foot hose or short section off the pump, and use
steel pipe for the balance of the horizontal distance to the
vertical line. This type of installation has been satisfactory
on many jobs being pumped in excess of 100 feet high. Line
pressures are always less using steel pipe as compared
to hose.
When pumping vertically using all hose, it is recommended
to not go higher than 50 feet with hose. The hose should
be tied off at intervals of 10 feet, if possible. Special
attention should be given when tying the hose off at the
top as the hose will have a tendency to stretch when
filled with concrete. This will increase the possibility of a
blockage at the point where the hose is tied off. To avoid
this, a long radius of 90-degree elbow is recommended.
The recommended place to tie off is on the hose, under
the clamp.
Hose Pulsation
A slight pulsation of the hose will always be noticeable near
the pump. Excessive pulsation of the hose near the pump is
normally due to higher than average line pressures caused
by stiff, harsh mixes or extremely long pumping distances.
In these extreme cases, the use of a 2-1/2" inside diameter
hose reduces line pressures, and the addition of slight
amounts of water to the mix, if permissible, will permit easier
pumping.The use of certain pumping admixtures may help.
If excessive pulsation exists in the hose, it is advisable to
use burlap or some means of wear protection under the
hose at points where the hose may wear through the outer
cover (e.g. over forms, steel, or sharp curbs).
Snap-Joint Couplings
When using Snap-Joint couplings with gaskets to join hose,
see that they are washed clean after each job. Keeping the
hose ends clean (heavy duty) is very important for the best
job setup. A thin coat of grease on the rubber gasket or
dipping both coupling and gasket in water before coupling
the hose will make for easier installation.
Fill the hopper with water after making sure that all sand
and rock have been removed from the manifold. Operate
the pump at full throttle and the 3/8-inch diameter hole
restriction will create sufficient back pressure to allow a
thorough inspection of all moving parts.
NOTICE
It is strongly recommended that steel pipe be used on all
vertical pumping for safety and convenience.

PAGE 18 — MAYCO LS300GK CONCRETE PUMP • OPERATION MANUAL — REV. #1 (10/14/22)
The Effects Of Excessive Heat AndTime On Concrete
Hot concrete, commonly referred to as a hot load, is
concrete that has been in the ready-mix truck in excess of
2–3 hours. On a hot day, this amount of time is even shorter.
A brief explanation of why heat and time affect concrete:
Concrete starts setting by drying up through a chemical
reaction.The catalyst to this reaction is heat.When pumping
a hot load, it is important to remember that when you have
to stop pumping for any reason, add water to the concrete
in the hopper and hand mix and move the concrete in the
hose every 5 minutes. If the shutdown time becomes too
long, wash out immediately.
If it is necessary to wait 1/2 hour or more for another load
of concrete, to prevent setting of the mix in the system it is
advisable to consider the following factors (A–D) affecting
the concrete:
a. How old is the concrete?
b. Is there an accelerator, calcium chloride, red label,
etc. in the concrete?
c. What is the ambient temperature (80–90 degrees)?
d. How much system do you have out and how stiff
is the mix you were pumping?
Preventing Mix Set-Up After Pump Shutdown
When the pump is stopped for any reason during a pour
(e.g. moving hose, waiting for ready-mix truck), the following
suggestions are offered:
1. Leave the hopper full of concrete at the time of
shutdown. It is important to not let the ready-mix driver
wash too much water into the hopper, as this could
cause separation of the concrete in the hopper.
2. If the shutdown period exceeds 2–3 minutes, turn off
the engine so the vibration does not separate the mix in
the hopper which can cause a blockage in the manifold
when the pump is restarted.
3. If it is necessary to wait 10 minutes or more for another
load of concrete, it is wise to start the pump and pump
6 or 8 strokes every 5 minutes to prevent setting of the
mix in the system. If waiting time is excessive, it would
be wise to wash out the pump and hoses and start over
when the new truck arrives.
GENERAL INFORMATION
4. When pumping stiff mixes and there is waiting time
between ready-mix trucks, it is advisable to add some
water to the last hopper of material and “hand mix” to
ensure an easier start with the following load.
5. When the pumping job requires a stiffer mix, the
following method is suggested for starting: Take a water
hose with a nozzle on it and apply water with a fine
spray to the concrete as it comes down the ready-mix
chute into the pump hopper after the slurry procedure
is completed and you are ready to start pumping.
6. Using this procedure will make it easier to pump
through the clean hose.
7. Hose sizing is very important:We strongly recommend
on harsh mixes, vertical pushes, stiff concrete,
shotcrete, or long pushes, that a 2-1/2" line be used
as far as possible. The advantages of using the 2-1/2"
line are improved pumpability, less pumping pressure
and less wear on the pump.
8. Following the pump operation, proper wash out of all
materials or “build-up” within the pump manifold and
hoses will prevent problems when starting the next job.
9. A thorough inspection of the drive components and
greasing of all bearings after each job will ensure
adequate lubrication and service to the pump which
is normally operating in wet, gritty conditions.
NOTICE
Once the concrete has reached the end of the hose,
DO NOT apply any more water in this manner as this
procedure is used for starting only.
NOTICE
Over-greasing any bearing on your Mayco pump will not
damage the bearing.

MAYCO LS300GK CONCRETE PUMP • OPERATION MANUAL — REV. #1 (10/14/22) — PAGE 19
GENERAL INFORMATION
Clearing The System After Mix Set-Up
If for any reason the mix should set up in the system, the
following procedure is suggested:
1. Disconnect the hose from the pump and wash the
pump out immediately.
2. Reconnect the hose and fill the hopper with water.
DO NOT try to push all the concrete out of all of the
hose lines at one time.
For example: If you had 200 feet of system out, you
would disconnect each hose. Clean it out by pushing
water through the first hose connected to the pump,
then continue progressing through all the hoses until
the entire system is clean.
3. If waiting time is excessive, it would be wise to wash
out the pump and hoses and start over when the new
truck arrives. This can be avoided by being observant
to the pump and system, also taking into consideration
the above factors (A–D) affecting the mix.
Clearing Concrete Blockage
WARNING
Hose Line Pressure
When disconnecting hoses, use EXTREME CAUTION.
The hose is under pressure. Hose could whip and cause
severe bodily harm.
NOTICE
If you repeatedly try to force your pump to push through
blockages due to separation of material in the hose or
manifold, you will soon have breakdowns and costly
repairs which are not covered under warranty.
If a blockage occurs, find where it is and clear it before
further pumping. DO NOT force the pump to clear
blockages. Increased pressure will only compound
the problem.
If a blockage occurs in a hose, walk the hose until you find
the point of trouble. The hose will be soft immediately past
the blockage. To clear the blockage:
1. Disconnect the hose at the first coupling past the
blockage. Be careful when disconnecting the hose.
Hose is under pressure. Hose could whip and cause
severe bodily harm.
2. Elevate the hose at that point with the blockage area
hanging down.
3. Using a hammer, pound the downstream edge of the
packed area until it is free to flow. Shake all of the sand
and gravel out to the end of the hose.
4. Before reconnecting the hose, start the pump and
run a small amount of concrete out to the end of the
hose. This will ensure that all of the separation is out
of the hose.
Clearing Shuttle Tube Blockage
The shuttle tube is plugged if volume at the discharge end
of the hose stops and the hydraulic oil pressure gauge
reads 3,200 psi or more.
To clear a plug in the shuttle tube, great care must be taken
as a dangerous condition will exist from pressure build-up
inside the shuttle tube. Using the shuttle valve, the concrete
can be pumped in reverse. Use the following procedures
to clear the shuttle tubes.
NOTICE
Damaged hoses with internal restrictions can cause
blockages.
WARNING
Joint Clamps
DO NOT open any of the delivery system joint clamps
during operation.The clamps are under pressure.Opening
the clamps during operation could allow high-pressure
material to escape and cause severe bodily harm.

PAGE 20 — MAYCO LS300GK CONCRETE PUMP • OPERATION MANUAL — REV. #1 (10/14/22)
Reverse Pumping Procedure
1. Switch the pump into reverse. With pump speed at a
medium-slow (approx. 12 strokes per minute) try to
pull the “pack” back into the hopper with 5 or 6 reverse
strokes.
2. Remix the concrete in the hopper.
3. Switch the pump into forward.If it is still plugged, repeat
the reverse pumping procedure three times.
4. If the concrete still does not move, proceed to the
Shuttle Tube Inspection Procedure.
Shuttle Tube Inspection Procedure
1. Stop the pump. Turn off the engine.
2. The senior or most experienced operator must warn all
others to stand at least 20 feet away from the machine
and turn their heads to face away from the pump.
3. Wearing safety glasses, stand beside the reducing
elbow at the pump outlet. Slip the end of a pry bar
(24-inch length of reinforcing steel rod) under the latch
of the hose clamp and flip it up.
4. Carefully knock the end of the hose away from the
reducer.
5. Chip the concrete out of the reducer with the pry bar.
6. Remove the reducer. From the discharge end, chip
the concrete out of the shuttle tube with the pry bar. If
the concrete cannot be loosened from the outlet of the
shuttle tube, remove the clean-out plug on the bottom
of the hopper to discharge the concrete.
7. Chip the blockage out with the pry bar.
8. Flush the shuttle tube with water.
9. Before resuming operation of the pump, perform
the above Reverse Pumping Procedure to relieve
pressure on the shuttle tubes.
GENERAL INFORMATION
The following is a brief explanation of how the concrete
cylinders, hydraulic cylinders, shuttle tube, valves, and
hopper work in sequence to pump concrete.
The hydraulic pressure is generated by a variable volume,
pressure-compensated, axial piston pump that is driven by
a diesel engine. The rod sides of the drive cylinders are
hydraulically connected together creating a “slave circuit,”
which allows hydraulic oil to transfer from one piston to
the other.
The two-part cycling sequence is initiated by an electrical
signal generated by two proximity switches activated by
the drive cylinder. The proximity switches are normally
open, magnetically sensing the movement of the main
drive cylinder. As the drive cylinder piston head passes
the proximity switch, an electrical signal is sent to the
solenoid-operated pilot valve which in turn directs pilot
oil to the four valves controlling the drive cylinder and the
shuttle cylinder.
WARNING
Transporting
It will be necessary at times to move your pump from
one job site location to another. Before moving the
pump, make sure to pump the remaining concrete out
of the hopper.
Moving the pump with a full hopper of concrete can
damage the axle, causing premature tire wear and
unsafe towing conditions.
NOTICE
Leaking manifold seals or hose coupling gaskets can
cause separation and subsequent jamming at that point.