Nilfisk-Advance 21KB User manual

PBU Propane Floor Burnisher
03/11 Revised 07/12 Form No. 56043153
Service Manual
Nilfisk-Advance “PBU” Machines: 56381402, 56381404, 56381405, 56381406, 56381407,
56381408 (Dust control unit), 56381409 (Dust control unit), 56381454
Nilfisk-Advance “Propane Stripper” Machine: 56381410
Diamatic Machines: 56381412, 56381413
English
21KB
21KBCAT
21KBCATCL
27KB
27KBCL
27KBCAT
21KBCATCLFC-
27KBCATCLDC
21KBCATCLST
MPS-1721
MPS-1727

Service Manual: PBU Floor Burnisher
Form Number 56043153 Page ii
Contents
General Informaon . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Service Manual Purpose and Applicaon . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Document Revision History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Other Reference Manuals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Convenons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Transporng the Machine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Cauons and Warnings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
General Machine Descripon . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Nameplate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Operator Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Know Your Machine — Major components: . . . . . . . . . . . . . . . . . . . . . . . . . 9
Specicaons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
Maintenance Schedule . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Burnishing System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
Maintenance and Adjustments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Replace burnishing disc pad gripper assembly. . . . . . . . . . . . . . . . . . . . . . . . 14
Replace Burnishing Disc Assembly Drive Belt. . . . . . . . . . . . . . . . . . . . . . . . . 15
Replace Drive Belt Tensioner. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Relocang Belt Tensioner Mounng Posion - Some 27 Inch Models . . . . . . . . . . . 16
Replace Drive Clutch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
Electrical System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19
Funconal Descripon. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19
Carb Gard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19
Carb Gard Normal Operaon . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Component Locaons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Troubleshoong . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Oxygen Sensor Test. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20
Wiring Diagrams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Engine System. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24
Funconal Descripon . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Ignion System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Ignion System Operaon Theory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Maintenance and Adjustments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Air Cleaner Element Cleaning and Inspecon . . . . . . . . . . . . . . . . . . . . . . . . 25
Engine Top End Cylinder Head Inspecon . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Engine Top End, Cylinder Head Cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Engine Top End, Cylinder Head Assembly Removal . . . . . . . . . . . . . . . . . . . . . 26
Engine Top End, Cylinder Head Assembly Installaon . . . . . . . . . . . . . . . . . . . .28
Engine Top End, Valve Clearance Inspecon . . . . . . . . . . . . . . . . . . . . . . . . . 29
Valve Clearance Adjustment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30
Valve Seat Inspecon. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31
Lubricaon System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Engine Oil Level Inspecon . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Engine Oil Change . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Oil Filter Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

Service Manual: PBU Floor Burnisher
Form Number 56043153 Page iii
Electrical System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Spark Plug Cleaning and Inspecon. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34
Air Cleaner . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Element Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .35
Element Installaon . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Element Cleaning and Inspecon . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .36
Troubleshoong . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Compression Measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Engine Troubleshoong Guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Starter Motor Troubleshoong Guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
Removal and Installaon . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
Ignion Coil Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
Ignion Coil Installaon . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .44
Spark Plug Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
Spark Plug Installaon . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .46
Spark Plug Cleaning and Inspecon . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
Spark Plug Gap Inspecon . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .46
LP Regulator Replacement Before Serial Number 3000083761. . . . . . . . . . . . . . .47
LP Regulator Replacement - Aer Serial Number 3000083760 . . . . . . . . . . . . . . .52
Replace Engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
Specicaons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .55
Engine Specicaons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
Ignion Coil Specicaons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
Special Tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

General InformationService Manual – PBU Propane Floor Burnisher 4
General Information
Service Manual Purpose and Application
This Service Manual is a resource for professional service technicians. It provides information for
understanding how the machine operates, where components are located, basic troubleshooting,
maintenance and mechanical service operations.
This manual covers the Nilsk-Advance models 56381402, 56381404, 56381405, 56381406, 56381407,
56381408, 56381409, 56381410 (propane stripper), 56381412 (21” Diamatic machine), and 56381413 (27”
Diamatic machine). The cover page of this manual lists each machine part number that the manual applies
to. Compare the model number of the machine you are working on to the model numbers listed on the cover
page to be sure you are using the correct manual.
Document Revision History
• November 2011
– Engine Fuel System and RPM changes.
◦ General Information - Brush Speed specications
◦ Engine System - Added section for adjusting regulator after serial number 3000083760. Updated
Specication table High Idle Speed values.
– Burnishing System - Added information for replacing the drive belt tensioner
Other Reference Manuals
The following documents contain parts information and instructions for machine operation:
• Parts List Form # 56091022 applies to the following models: 56381402 (21KBCAT), 56381404 (21KB),
56381405 (27KB), 56381406 (27KBCL), 56381407 (27KBCAT)
• Parts List Form # 56091023 applies to the following models: 56381408 (21KBCATCLDC), 56381409
(27KBCATCLDC)
• Parts List Form # 56091024 applies to the following model: 556381410 (21KBCATCLST))
• Parts List Form # 56091025 applies to the following models: 56381412 (MPS-1721), 56381413 (MPS-1727)
Conventions
Forward, backward, front, rear, left or right are intended with reference to the operator’s position, that is to
say in operating position with the hands on the handlebar.

General InformationService Manual – PBU Propane Floor Burnisher 5
Transporting the Machine
.
Caution! Before transporting the machine on an open truck or trailer, make sure that
• The machine is tied down securely.
• All access doors and covers are secured (tape and strap as needed).
Cautions and Warnings
Danger! It is the owner/operator’s responsibility to ensure that an air exchange blower either
of positive or negative pressure is used in any location where a propane floor care
machine is being operated to support a sufficient fresh air supply to the operator
during use of such a machine. OSHA and other County, State, or Federal Agencies
publish guidelines for safe machine usage regarding exhaust emissions and CO
exposure in the workplace. Failure on the part of the owner/operator to ensure that a
propane floor care machine is operated safely in accordance with OSHA or local state
indoor air quality guidelines in a given location may lead to injury, sickness or even
loss of life. To be completely aware of what local authorities may require, contact the
Fire Marshal of your community.
This Owner’s Manual/Safety Procedures Guide has been prepared for the promotion
of educational purposes only and does not claim or assume any responsibility for the
operator’s actions or safety.
Danger! All LPG (Liquid Propane Gas) powered engines, including this engine, produce Carbon
Monoxide (CO). It is a LETHAL POISON that is a colorless, odorless, tasteless, and
non-irritating gas. It is produced by incomplete combustion of carbonaceous material
such as propane (LPG).
Failure to provide for proper venting of CO produced during the operation of
combustion powered engines may result in SERIOUS INJURY OR DEATH to the
operator and those in the contaminated area.
The effects of CO can be experienced at different exposure levels, depending on
the health of the individual. Conditions that affect the tolerance of the individual are
smoking, age, temperature, humidity, and other conditions.
Warning: Read and understand The Operators Manual completely before using this machine.
This document explains how CO produced can be managed to reduce the risk of
carbon monoxide poisoning. All distributors, owners, and operators should be aware
of the potential effects of CO and the methods used to prevent over exposure. We are
dedicated to our customers, their safety, and providing information, services, and
products that meet those needs.

General InformationService Manual – PBU Propane Floor Burnisher 6
Warning: The Products sold with this Manual contain or may contain chemicals that are
known to certain governments (such as the State of California, as identified in its
Proposition 65 Regulatory Warning Law) to cause cancer, birth defects or other
reproductive harm. In certain locations (including the State of California) purchasers
of these Products that place them in service at an employment job site or a publicly
accessible space are required by regulation to make certain notices, warnings or
disclosures regarding the chemicals that are or may be contained in the Products at
or about such work sites. It is the purchaser’s responsibility to know the content of,
and to comply with, any laws and regulations relating to the use of these Products
in such environments. The Manufacturer disclaims any responsibility to advise
purchasers of any specific requirements that may be applicable to the use of the
Products in such environments.
Warning: Deployment of a monitor/detector is essential for the safe operation of any
equipment that has the potential to produce CO. CO sensors/detectors became
available on the mass market around 1978. At present several brands sell in the
fifty-dollar range. The main differences between the technologies involved are
battery or electric and Semiconductor or Biomimetic types. Detectors for carbon
monoxide (CO) are manufactured and marketed for use in either the home or
occupational industrial settings. The detectors for home use are devices that will
sound an alarm before CO concentrations in the home become hazardous. There is
an Underwriters Laboratories, Inc., performance standard (UL 2034) for residential
CO detectors. Detectors currently available on the market are battery-powered, wall
mount, Operator worn portable personal protective, plug-in, or hard-wired. Some
models incorporate a visual display of the parts per million (ppm) concentration
of CO present in the home. For more information on CO detectors for home use,
call the Consumer Product Safety Commission Hotline at 1-800-638-2772. CO
detectors for use in residential settings are not designed for use in typical workplace
settings. Monitoring requirements in an occupational setting are different from
monitoring requirements in the home. In the workplace, it is frequently necessary
to monitor a worker’s exposure to carbon monoxide over an entire work shift and
determine the time-weighted average (TWA) concentration of the exposure. It may
also be necessary to have carbon monoxide monitors with alarm capabilities in the
workplace. The direct-reading instruments are frequently equipped with audio and/
or visual alarms and may be used for area and/or personal exposure monitoring.
Some have microprocessors and memory for storing CO concentration readings
taken during the day. It is significant to note that some of the devices mentioned
for workplace CO monitoring are not capable of monitoring TWAs, and not all are
equipped with alarms. The appropriate personal protective monitor must be chosen
on an application-by-application basis. For more information on the availability
of workplace CO monitors or their application, call the National Institute for
Occupational Safety and Health at 1-800-35-NIOSH (1-800-356-4674).

General InformationService Manual – PBU Propane Floor Burnisher 7
Warning: The proper maintenance of equipment is vital to safe operation. LPG engines
are dependent on engine tune up, and air filter replacement. CO concentration
(production) skyrockets when the air to fuel ratio becomes fuel rich. Follow the
recommended Maintenance Schedule for the engine found in the Engine Operator/
Owner Manual as well as the Maintenance And Adjustments schedule found in the
Propane Floor Equipment Operator’s Manual that were supplied with the equipment.
CO SAFETY EQUIPMENT AVAILABLE BY MANUFACTURER
−Carb Gard automated emissions monitoring will shut down the engine when high emissions are
detected.
− Three-way type catalytic converter to scrub CO, Hydro Carbons (HC), and Nitrides of Oxygen
(NOx) from the engine exhaust providing the lowest possible emissions
− NOTE: Dead Stop CO Detector provided in Literature Pack. Replacement part number 98758A.
CO SAFETY EQUIPMENT AVAILABLE ON THE MARKET
− Positive or negative pressure high volume ventilation blower capable of exchanging complete
room air volume to maintain CO levels below OSHA exposure limits.
− Digital combustion analyzers for tail pipe emissions monitoring
− OSHA Approved CO Monitor
Caution: Overfilling the propane tank is the number one cause of problems with a propane
machine. This can cause the engine to run poorly or not at all.
In addition, overfilling allows liquid propane to enter the fuel control system, possibly
ruining the lockoff/regulator assembly. This voids the warranty on affected parts of
the machine. To avoid problems, read and understand fully, the section “Filling and
Storing Propane Tanks.”
General Machine Description
The PBU (Propane Floor Burnisher) is manufactured for two applications: a buffer/burnisher and a oor
stripper. Both designs are portable. Buffers operate at high speed to produce high gloss oor surfaces. The
unit is powered by a 4-stroke, air-cooled, v-twin, liquid propane-fueled engine. During operation the unit
bufng wheel contacts the oor to provide bufng action. Operator walking speed behind the unit determines
results. The operator should avoid loose tile, electric outlets, door thresholds and any object which may
come in contact with the pad, other than the oor itself. When equipped, the Carb Gard system is a warning
device that alerts the operator to the need for engine service. Carb Gard monitors an oxygen sensor for an
indication of relative air/fuel mixture. If the mixture exceeds an allowable limit for more than one minute,
Carb Gard will shut down the engine.

General InformationService Manual – PBU Propane Floor Burnisher 8
Nameplate
The nameplate contains important identication information which will be needed when ordering parts:
Model (Name), Part No. (Part number of the machine which is often referred to as the “Model Number”), and
Serial Number.
Nameplate
Figure 1. Nameplate Location Figure 2. Nameplate Location
Operator Controls
Ignition
Key
Engine
Hourmeter
Ignition
Key
Engine
Hourmeter
Carb Gard
Indicators
Figure 4. Controls, Non-Carb Gard Figure 5. Controls, Carb Gard

General InformationService Manual – PBU Propane Floor Burnisher 9
Know Your Machine — Major components:
LP Regulator
LP Lock
Off Valve
Starter
Air Cleaner
Cover
Oxygen
Sensor Muffler
Air Cleaner
Element
Carburetor
Oil Fill and
Dip Stick
Oil Pressure
Switch
Oil Filter
Battery Location
(with Dust Control)
Carb Gard
Controller
Battery Location
(without Dust Control)
Carb Gard
Control Panel
Figure 3. Major Components

General InformationService Manual – PBU Propane Floor Burnisher 10
Specifications
(See other system chapters for specications not listed here.)
Model 21KBCAT 21KB 27KB 27KBCL 27KBCAT
21KBCATCLST
Part
Number 56381402 56381404 56381405 56381406 56381407
Pad Size 21” (53 cm) 21” (53 cm) 27” (68 cm) 27” (68 cm) 27” (68 cm)
Engine 603CC KAWASAKI
Catalytic
Mufer
Yes No No No Yes
Carb Gard No No No No No
Clutch None None None Centrifugal None
Pad Speed
Eng. @
3600 RPM
Pad Speed
2100 RPM Pad Speed 2100 RPM Pad Speed 1500 RPM Pad Speed 1500 RPM Pad Speed 1500 RPM
Pad Speed
Eng. @
3000 RPM
Pad Speed
1750 RPM Pad Speed 1750 RPM Pad Speed 1250 RPM Pad Speed 1250 RPM Pad Speed 1250 RPM
Propane
Tank 20 lb. (9.1 kg) Capacity, 80% Safety Fill
Auto Fuel
Shutoff Yes Yes Yes Yes Yes
Low Oil
Shutdown Yes Yes Yes Yes Yes
Hour Meter Yes Yes Yes Yes Yes
Sound
Pressure
(ISO
11201)
87 dB LpA, 3dB KpA
Productivity
Rate 25,000 ft2/hr (2,322 m3/hr) 25,000 ft2/hr (3,066 m3/hr)
Agency
Approvals EPAplus ULApproved Propane Components
"CARB
Certied
(California
Air Re-
source
Board)"
Yes Yes Yes Yes Yes
Weight 212 lbs. /
96 kg. 214 lbs. /
97 kg. 240 lbs. / 109 kg. 246 lbs. / 111 kg. 238 lbs. / 108 kg.
Length 51.5”
(131.8 cm) 51.5” (131.8 cm) 59” (149.9 cm) 59” (149.9 cm) 59” (149.9 cm)
Width 23.3” (59 cm) 23.3” (59 cm) 29.3” (74.4 cm) 29.3” (74.4
cm) 29.3” (74.4 cm)
Height 43” (109.2 cm) 43” (109.2 cm) 43” (109.2 cm) 43” (109.2
cm) 43” (109.2 cm)
Warranty 2 Years Parts & Labor

General InformationService Manual – PBU Propane Floor Burnisher 11
Model 21KBCATCLDC 27KBCATCLDC 27KBCATCLST MPS-1721 MPS-1727
Part Number 56381408 56381409 56381410 56381412 56381413
Pad Size 21” (53 CM) 27” (68 cm) 21” (53 CM) 21” (53 CM) 27” (68 cm)
Engine 603CC KAWASAKI
Catalytic
Mufer
Yes Yes Yes Yes Yes
Carb Gard Yes Yes Yes Yes Yes
Clutch Centrifugal Centrifugal Centrifugal Centrifugal Centrifugal
Pad Speed
Eng. @ 3600
RPM
2100 RPM 1500 RPM 1400 RPM 1400 RPM 1400 RPM
Pad Speed
Eng. @ 3000
RPM
1750 RPM 1250 RPM 1170 RPM 1170 RPM 1170 RPM
Propane Tank 20 lb. (9.1 kg) Capacity, 80% Safety Fill
Auto Fuel
Shutoff Yes Yes Yes Yes Yes
Low Oil
Shutdown Yes Yes Yes Yes Yes
Hour Meter Yes Yes Yes Yes Yes
Sound
Pressure
(ISO 11201)
87 dB LpA, 3dB KpA
Agency
Approvals EPA plus ULApproved Propane Components
"CARB
Certied
(California
Air Resource
Board)"
Yes Yes Yes Yes Yes
Weight 292 lbs /
132.5 kg. 302 lbs / 137 kg 242 lbs / 110 kg. 248 lbs / 112.5 kg. 292 lbs / 132.5 kg.
Length 66”
(167.4 cm) 69” (175.3 cm) 51.5” (131.8 cm) 51.5” (131.8 cm) 59” (149.9 cm)
Width 23.3”
(59 cm) 29.5”
(74.9 cm) 23.3” (59 cm) 23.3” (59 cm) 29.3” (74.4 cm)
Height 43”
(109.2 cm) 43” (109.2 cm) 43” (109.2 cm) 43” (109.2 cm) 43” (109.2 cm)
Warranty 2 Years Parts & Labor

General InformationService Manual – PBU Propane Floor Burnisher 12
Model 21KBCATCL
Part Number 56381454
Pad Size 21” (53 CM)
Engine 603CC KAWASAKI
Catalytic
Mufer
Yes
Carb Gard No
Clutch Centrifugal
Pad Speed
Eng. @ 3600
RPM
2100 RPM
Pad Speed
Eng. @ 3000
RPM
1750 RPM
Propane Tank 20 lb. (9.1 kg) Capacity, 80% Safety Fill
Auto Fuel
Shutoff Yes
Low Oil
Shutdown Yes
Hour Meter Yes
Sound
Pressure
(ISO 11201)
87 dB LpA, 3dB KpA
Agency
Approvals EPA plus ULApproved Propane Components
"CARB
Certied
(California
Air Resource
Board)"
Yes
Weight 218 lbs / 99 kg.
Length 51.5” (131.8 cm)
Width 23.3” (59 cm)
Height 43” (109.2 cm)
Warranty 2 Years Parts & Labor

General InformationService Manual – PBU Propane Floor Burnisher 13
Maintenance Schedule
ITEM
Interval
Daily 8 Hour
(Break In)
Every
25
Hours
Every
50
Hours
Every
100
Hours
Every
200
Hours
Every
300
Hours
Check or clean air intake screen •
Check for fuel and oil leakage •
Check for loose or lost nuts and
screws •
Tighten nuts and screws •
Check battery electrolyte level •
Check and add engine oil •
Change engine oil • •
Change oil lter •
Clean air cleaner foam element •
Replace air cleaner paper element •
Check pad driver for loose parts • •
Check belt for wear or slippage • •
Check engine pulley for tightness • •
Check wheel bolts • •
Check engine mount bolts • •
Check handle bolts • •
Check for leakage of engine oil at
the various seals • •
Change dust control lter •
Check and adjust engine valve
clearance •
Clean and lap valve seating
surface •
Clean dust and dirt from cylinder
and cylinder head ns
•
Clean and re-gap spark plugs •
Clean combustion chambers •
Return machine to authorized
service center for overall checkup. •

Burnishing System 14Service Manual – PBU Propane Floor Burnisher
Burnishing System
Replace burnishing disc pad gripper assembly.
1. Use an open end wrench to grip the bolt that
secures the burnishing disc assembly bearing.
Brace wrench against adjacent bolt to prevent
the bearing from rotating.
Figure 6 Grip Bolt, Burnishing Disc Assembly
Figure 7 Remove Pad Gripper Assembly
2. Rotate the pad gripper assembly counter-
clockwise to remove.
3. To replace, thread pad gripper assembly onto
shaft and rotate clockwise until secure.
Figure 8 Replace Pad Gripper Assembly
Maintenance and Adjustments

Burnishing System 15Service Manual – PBU Propane Floor Burnisher
Replace Burnishing Disc Assembly Drive Belt.
An idler assembly is used to keep the burnishing disc
drive belt tight. The idler assembly must be rotated
slightly to free the belt for removal.
Figure 9 Idler Assembly, No Clutch
Figure 10 Idler Assembly, With Clutch
Idler
Assembly
Idler
Assembly
Figure 11 Pull Down on Idler Assembly
1. To remove tension on the drive belt, use
a wrench to grip the idler assembly. Pull
down on the wrench to rotate the idler
assembly slightly and free the belt.
2. Position the replacement belt on the drive
(or clutch) and burnishing disc pulleys.
Again, use the wrench to pull the idler
assembly down slightly. Position the belt
in the idler assembly pulley and allow
the idler assembly to return to its normal
position. Check the belt to make certain
that it is fully seated in all three pulleys.

Burnishing System 16Service Manual – PBU Propane Floor Burnisher
Replace Drive Belt Tensioner.
Note: On some 27 inch models (56381405, 56381406,
56381407,56381413) the tensioner location should be
updated when replacing the tensioner, if it has not
already been moved. See “Relocating Belt Tensioner
Mounting Position “ below for further information.
1. Remove the drive belt.
2. Remove the tensioner.
3. Install the tensioner with the mounting bolt
nger tight and install the drive belt.
4. Using a large wrench on the large nut of the
tensioner arm and aback up wrench on the
mounting bolt, rotate the arm against spring
pressure until the indicator marks on the
tensioner arm align near the third index mark
on the stationary tensioner body as shown in
the photo. Tighten the mounting bolt to hold the
tensioner in place. Crank the engine over a few
times to seat the belt and then recheck the belt
tension. If it is incorrect, loosen the mounting
screw and reposition the tensioner as necessary.
Relocating Belt Tensioner Mounting
Position - Some 27 Inch Models
These instructions only apply to the following models:
56381405, 56381406, 56381407,56381413
1. Remove the drive belt.
2. Loosen all 3 engine mounting bolts and back out
approximately 1/2 inch (13mm). This will allow
you to lift the engine slightly and will aid in
installing the tensioner mounting bolt in the new
location later.
3. Remove the tensioner.
Engine
Mounting
Bolts

Burnishing System 17Service Manual – PBU Propane Floor Burnisher
4. Working from the bottom of the deck, locate the
position of the new mounting bolt hole by scribing
two arcs from xed positions and nding their
intersecting point.
a. Using a tape measure scribe the rst arc
3 11/16th inches from the center of the original
tensioner mounting bolt.
b. Using a tape measure scribe the second arc 7
inches from the center of the forward engine
mounting bolt head.
5. Drill a 3/8 hole where the arcs intersect.
6. Install tensioner mounting bolt through the new
hole just made and install the tensioner nger
tight.
7. Plug the old mounting bolt hole using a bolt and
nut.
8. Tighten the engine mounting bolts.
New
Location
Old
Location
Drill 3/8
inch hole

Burnishing System 18Service Manual – PBU Propane Floor Burnisher
Replace Drive Clutch
1. To replace the drive clutch, rst remove the
drive belt. See “Replace Burnishing Disc
Assembly Drive Belt” above for the procedure
to remove the drive belt.
2. Using an impact wrench, remove the bolt that
secures the clutch. Remove clutch.
3. Apply Loctite 243 to the bolt the secures the
clutch. Position the replacement clutch. Insert
the bolt and torque to 40 ft-lb.
An alternate method can be used to remove the
clutch. This method requires a vicegrip or channel
locking pliers.
1. Use the vicegrip or pliers to grip the washer at
the end of the clutch.
2. Use a wrench or socket to remove the bolt that
secures the clutch. Remove clutch.
3. Apply Loctite 243 to the bolt the secures
the clutch. Position the replacement clutch.
Insert the bolt and secure the washer with the
vicegrip or pliers. Tighten the bolt. If a torque
wrench is available, torque the bolt to 40
ft-lb.
Clutch
Bolt
Washer
Figure 12 Replace Clutch
9. Using a large wrench on the large nut of the
tensioner arm and a back-up wrench on the
mounting bolt, rotate the arm against spring
pressure until the indicator marks on the
tensioner arm align near the third index mark
on the stationary tensioner body as shown in
the photo. Tighten the mounting bolt to hold the
tensioner in place. Crank the engine over a few
times to set the belt and then recheck the belt
tension. If it is incorrect, loosen the mounting
screw and reposition the tensioner as necessary.

Electrical System 19Service Manual – PBU Propane Floor Burnisher
Electrical System
Functional Description
Carb Gard
Carb Gard is a warning device to alert the operator that the engine needs to be serviced. The Carb Gard
system includes an oxygen (O2) sensor. The oxygen sensor is mounted in the exhaust manifold to monitor
how much unburned oxygen is in the exhaust as the exhaust exits the engine. The O2 sensor produces
electrical voltage when it gets hot. It will generate approximately 1.0 volts when the fuel mixture is rich and
there is little unburned oxygen in the exhaust. When the mixture is lean, the sensor output voltage will drop
down to 0.2 volts or less. When the air/fuel mixture is balanced the oxygen sensor will generate around .5
volts.
Carbon monoxide (CO) may be produced if the engine operates with a fuel mixture that is too rich. Carbon
monoxide can be highly toxic. If the Carb Gard system senses too high of a voltage from the oxygen sensor
(resulting from a fuel mixture that is too rich), the engine will be shut down to prevent a possible build-up of
carbon monoxide in the work area. See Carb Gard Normal Operation description below.
Carb Gard Normal Operation
1. Upon starting the engine, the GREEN “Alert” LED will begin ashing. It will continue ashing for 3
minutes. This allows the engine and the oxygen sensor (mounted in the exhaust manifold) enough time
to warm up. During this time, it is okay to operate the burnisher.
2. After 3 minutes, the Alert LED will stop ashing.
(a) If the engine is idling, then the YELLOW “Idle” LED will begin ashing. This allows the engine to
idle for up to 2 minutes.
(b) After 2 minutes, the engine will shut down and the idle LED will remain solid to notify the operator
why the machine shut down. (Note: If this occurs, simply turn the key switch to OFF. This will reset
the Carb Gard. Restart the engine normally to continue operation).
(c) If at any time before the 2 minute countdown, the engine is revved up to full throttle, the LED will
stop ashing and the Carb Gard will begin monitoring the oxygen sensor.
(d) If the engine is allowed to slow back down to the idle position, the idle LED will again start ashing
for another 2 minutes.
Note: Every time the engine is revved up and allowed to slow down, the 2 minute countdown
restarts itself
3. Once the engine is revved up, the Carb Gard begins monitoring the oxygen sensor.
(a) If at any time during full throttle the Carb Gard senses a higher than normal oxygen sensor output
voltage, it will activate the RED “Service” LED and it will begin ashing.
(b) If the RED service LED ashes continuously for 1 minute, then the engine will shut down and the
RED service LED will remain solid to notify the operator why the engine shut down.
Note: Carb Gard continuously monitors O2 sensor electrical voltage. If the voltage drops into the
normal range, the service LED will stop ashing. If the voltage rises to higher than normal,
the service LED will start ashing again. ONLY after the service LED continuously ashes
for 1 minute will it shut down the engine.

Electrical System 20Service Manual – PBU Propane Floor Burnisher
Component Locations
Carb Gard
System Panel
Carb Gard
Controller Carb Gard
Oxygen Sensor
Figure 13 Carb Gard System Components
Oxygen Sensor
Requires digital multi-meter.
1. Connect jumper between oxygen sensor lead
and harness plug.
2. Connect positive multimeter lead to the
jumper wire.
3. Connect negative multimeter lead to chassis
ground.
4. Remove air cleaner housing.
5. Start and warm up engine. Set the
multimeter to VDC.
6. While at high idle with warm engine, note
the VDC meter reading.
7. Remove the air intake lter.
Jumper Wire
Connect Positive
Connect Ground Air Intake Filter
Oxygen Sensor Test
Troubleshooting
Check the following if unexplained engine shutdown occurs:
• Oil pressure switch function (assumes engine can be restarted).
• Fuel lock off solenoid function.
• Primary regulator pressure. If too high, the regulator may require replacement.
• If the primary regulator pressure is within specications, the regulator orice may be faulty and the
regulator may require replacement.
If the above items have been eliminated as causes of engine shut down, test the Carb Gard oxygen sensor
for possible malfunction. If the oxygen sensor test described below determines that the sensor is functioning
properly, replace the Carb Gard system.
Figure 14 Sensor Test