Kärcher KMR 1250 User manual

5.905-262

09.02

KMR 1250

(KMR 1250 B, KMR 1250 LPG, KMR 1250 D)

1.091- . . .

Service Manual

KARCHER

KMR

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KARCHER

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5.905-122

4-Stroke Internal

Combustion Engines

Service-Manual

5.905-122

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Foreword KMR 1250 B, LPG, D

Foreword

Good servicing requires extensive and relevant training as well as comprehensible reference

documents.

We therefore offer basic and advanced training courses for the full range of our products to all

service technicians on a regular basis.

In addition, we produce service manuals for the major units in our product line. While these are

ideal for initial use as instruction manuals, they are designed to serve as an essential reference

in the future.

To augment our product-related communications, we regularly distribute service information

bulletins providing details about ongoing product development.

Copyright Notice

be reproduced, stored in a retrieval system, or transmitted in any form or by any means, i.e.,

electronic, mechanical, photocopying, recording or otherwise, without the written permission of

Alfred Kärcher GmbH & Co.

ALFRED KÄRCHER GmbH & Co.

Customer Service Training

P.O. Box160

71349 Winnenden, Germany

http://www.karcher.de

3

KMR 1250 B, LPG, D Table of Contents

Contents

Unit functions ...........................................................................................................4-15

Overview ............................................................................................................................... 4-5

View from front ..........................................................................................................................6

Controls.....................................................................................................................................7

Gasoline Engine (HONDA GX 270)........................................................................................ 8-9

LP Gas Engine (HONDA GX 270).......................................................................................10-11

Diesel Engine (YANMAR L 70 AE-DE) ............................................................................... 12-13

Steering and Drive Power........................................................................................................14

Sweeping system....................................................................................................................15

Troubleshooting Information...................................................................................4-15

Starter Fails to Turn Engine ............................................................................................... 16-18

Starter Turns Engine but Engine Fails to Start................................................................... 19-20

Engine Runs but Machine Fails to Move............................................................................ 21-25

Maintenance Procedures (gasoline and LPG engine) ....................................................... 26-27

Maintenance Procedures (LPG engine) ............................................................................ 28-29

Maintenance Procedures (diesel engine) .......................................................................... 30-31

Parking Brake – No Function ...................................................................................................32

Brush Roller – Poor Performance ..................................................................................... 33-34

Brush Roller – No Rotation......................................................................................................35

Side Brushes – Poor Sweeping Performance.........................................................................36

Excessive Unit Dusting...................................................................................................... 37-41

Filter cleaning Motor – No Function .........................................................................................42

Hydraulic Unit – No Function ...................................................................................................43

Debris Container – Very Slow Ascent......................................................................................44

Debris Container – No Full Ascent...........................................................................................45

Excessive Steering Free Play..................................................................................................46

Hydraulic Block Diagram .......................................................................................48-49

Electrical Circuit Diagram ......................................................................................50-55

Maintenance Procedures for B, LPG & D Models ................................................56-57

Technical Specifications........................................................................................58-59

Special Tools...........................................................................................................60-62

Index ........................................................................................................................63-65

4

Unit Functions KMR 1250 B, LPG, D

Drive system

– When the hood is lifted up toward the rear, all

components become accessible for mainte-

nance purposes.

– Hydrostatic transmission with mechanical free-

wheeling device provides variable control of

forward and reverse driving speeds.

– Parking brake lever actuates transmission-

mounted disc brake.

– No foot brake required. Transmission provides

braking effect.

– Transmission, impeller fan, brush roller and

side brushes are belt-driven.

– Rear wheels are chain-driven.

– To start engine, driver must occupy operator

seat (seat contact switch).

– Discharge of debris container via electrically

driven hydraulic unit.

Sweeping system

– Brush roller counter-rotates against direction

of unit motion (throw-over principle).

– Debris container is located at rear of brush

roller.

– Two-position adjustment of brush roller via

control lever:

Center position: Rigid brush roller suspension

for level surfaces.

Bottom position: Floating brush roller suspen-

sion for uneven surfaces.

– Quick-change brush roller replacement. No

tools required.

– Side brush automatically extends outward

when lowered.

– Coarse-dirt flap accommodates pickup of bev-

erage cans, etc.

– Hydraulic discharge of debris container in

raised position (two-hand operation).

Suction and filtering system

– Dust pickup at brush roller.

– Large-capacity dust filter with mechanical dust

removal.

– Each time engine is shut off, dust filter is sub-

jected to automatic cleaning cycle of approx.

15-second duration.

– Impeller fan with closeable exhaust-air hatch

for wet-sweeping operation.

– Quick-change dust filter replacement. No tools

required.

– Impeller fan driven by elastic belt. No tension

adjustment required.

5

KMR 1250 B, LPG, D Unit Functions

Engine KMR 1250 B

– Single-cylinder, air-cooled gasoline engine

(HONDA GX 270) w/ electric starter. Uses

standard grade unleaded gasoline.

– Engine features oil level sensor.

Engine 1250 LPG

With the exception of the conversion to run on

liquefied petroleum gas (LPG), the unit is iden-

tical to the basic KMR 1250 B version.

– The gasoline engine is the same as in the KMR

1250 B (HONDA GX 270).

– The LP gas cylinder is mounted behind the

driver’s seat. As the gasoline tank is discon-

nected, its use is strictly prohibited.

– The carburetor has been converted to LP gas

operation.

– The engine compartment accommodates an

additional gas regulator required to adjust the

air/fuel mixture for the engine.

– The mechanical choke has been converted to

electrical control; it acts upon the gas regula-

tor.

Engine 1250 D

With the exception of the different engine type,

the unit is identical to the basic KMR 1250 B

version.

– Single-cylinder, air-cooled diesel engine (YAN-

MAR L 70 AE-DE) w/ electric starter.

– Features compression release for short-term

operation to help overcome top dead center

when starting the engine.

6

Unit Functions KMR 1250 B, LPG, D

View from front

1 Gas cylinder (LP Gas)

2 Steering wheel

3 Driver seat

4 Lifting mechanism for debris container

5 Rear wheel, chain-driven

6 Fuel tank for KMR B / D

7 Engine KMR B / LPG / D

8 LH side brush (option)

9 Front wheel

10 Head lights

11 RH side brush

12 Controls (see page 7)

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KMR 1250 B, LPG, D Unit Functions

1 Lever dust pickup, Close / Open

2 Button clean dust filter (S2)

3 Button lower debris container (S6)*

4 Button raise debris container (S8)*

5 Button tilt debris container (S7)*

6 Lever parking brake

7 Lever coarse-dirt flap

8 Headlight switch (S4)

9 Operating hours counter

10 Button two-hand operation, hydraulic (S5)

11 Lever LH side brush, Raise / Lower

(option)

12 Lever brush roller, Raise / Lower

(suspension: rigid or floating)

13 Lever RH side brush, Raise / Lower

14 Throttle lever

15 Button horn (S10)

16 Ignition switch (S1)

17 Choke

18 Drive pedal

ORIGINAL

and

REVISED

* Function available only in conjunction

with two-hand operation button (10).

( ) See circuit diagram.

Controls

11 12 13 14 16 17 16

10

9

8

7

6

5

4

3

2

1

15

14

15

1818

16

15

14

17

8

Unit Functions KMR 1250 B

Gasoline Engine (HONDA GX 270)

1 Stop screw, throttle valve

2 Idle jet

3 Bypass

4 Throttle valve

5 Idle orifice

6 Idle jet bore and idle air channel

7 Carburetor throat (venturi)

8 Idle air inlet

9 Choke valve

10 Main air jet

11 Idle system

12 Emulsion tube

13 Air orifice

14 Float chamber

15 Main jet

16 Adjusting screw, idle mixture

17 Fuel inlet

18 Inlet, float valve

19 Float

20 Float valve w/ float needle

21 Float

21 20 1819 17 5 15 14

13

12

9

10

7

8

642

1

16

33

3

11

5

9

KMR 1250 B Unit Functions

Gasoline Engine (HONDA GX 270)

Float system

When float chamber (14) is empty, fuel passes

from fuel tank into float chamber (14) via the float

valve inlet (18). The rising fuel level causes the

float (21) to be raised.

The inflow of fuel is interrupted when the float

(21) causes the float valve to close. Drawing fuel

for engine operation from the float chamber (14)

causes the float (21) to be lowered, which in turn

opens the float valve (18).

This cyclical procedure ensures a constant level

of fuel inside the float chamber (14).

Float chamber equalization

On the carburetor side, the airspace inside the

float housing is connected with the outside at-

mosphere by means of a channel. This facili-

tates the equalization of the pressure equilibri-

um inside the float chamber as the fuel level ris-

es or falls.

Idling operation

When the engine is idling, the throttle valve (4) is

fully closed.

– This causes negative pressure to occur be-

tween the throttle (4) and the crown of the

engine piston, with the latter moving toward

bottom dead center while the intake valve is

open.

– The atmospheric pressure inside the float

chamber (14) then causes fuel to be con-

veyed through the main jet (15) and idle jet

(2).

– The idle jet (2) controls the flow of fuel through

the idle bypass channel (3). The fuel then

blends with the air being drawn in through

the idle air channel (6).

– The resulting air/fuel mixture then flows into

the engine.

– The idle mixture adjusting screw (16) con-

trols the volume of air/fuel mixture that is al-

lowed to flow through the idle orifice (5).

Partial load operation

Engine speed rises when the throttle valve (4)

opens, and the volume of the air/fuel mixture

being drawn through the idle jet (2) increases.

Full load operation

In full load operation, the throttle is wide (4) open:

– Air flows through the carburetor throat, or

venturi (7). Because the diameter of the ven-

turi outlet is smaller than that of the intake,

the air is accelerated as it passes through.

This increased flow velocity causes nega-

tive pressure to occur at the outlet side of the

main jet (15).

– Pressure inside the float chamber (14) is

equalized via an atmospheric relief channel.

Because atmospheric pressure is higher than

the pressure in the carburetor throat (7), fuel

is transported from the float chamber (14),

and pressed through the main jet (15) into

the emulsion tube (12).

– The air flowing through the main air jet (10)

is blended with the fuel that is flowing through

the orifices of the emulsion tube (12).

– This mixture is then drawn into the carbure-

tor throat (7), where it is enriched with more

air before passing into the engine.

Choke system function

The choke valve (9) should be closed only when

starting a cold engine. This causes the following

to happen:

– The closed choke valve (9) allows less air to

be drawn into the carburetor throat (7).

– However, the fuel volume being drawn in

through the main jet (15) remains the same.

– This causes the fuel component in the air/

fuel mixture to rise, with the richer mixture

providing easier engine starting.

Note:

For information on other maintenance and

adjustments of the engine, refer to the Serv-

ice manual „4-Stroke Internal Combustion

Engines“ (5.905-122).

10

Unit Functions KMR 1250 B, LPG, D

1 Valve guard

2 LP gas line

3 Cylinder shutoff valve

4 Outlet tube

5 LP gas cylinder

6 Sun shield

7 LP gas in gaseous state

8 LP gas in liquid state

9 Carburetor

10 Engine

11 Vacuum line

12 LP gas line

13 Gas filter

14 Solenoid valve, gas supply

15 Mixture control screw (MIN eng. speed)

16 Gas regulator

17 Choke lifting solenoid

18 Mixture control screw (MAX eng. speed)

LP Gas Engine (HONDA GX 270)

11

14

8

17

16

18

9

10

7

654

2

1

3

15 1314 12 11 12

16

15

18

13

11

KMR 1250 B, LPG, D Unit Functions

– The presence of frost on any part of the LP gas

system indicates a possible leak. Close the

cylinder shutoff valve (3) immediately. Apply

suitable leak detection medium (soapy water

or Leak Detecting Spray 6.282-033) to gas

lines, solenoid valve, gas regulator and gas

hose to carburetor. Open cylinder shutoff valve

(3), and check for formation of bubbles. The

unit may be returned to service only after thor-

ough repairs have been carried out by ap-

proved specialists.

Note:

The LP gas system of the unit must be in-

spected by a licensed expert in 6-month

intervals. The results of each inspection must

be made available in the form of a test cer-

tificate.

– An expert is deemed to be a person who, based

on his professional education and skills, pos-

sesses sufficient knowledge of, and expertise

in, the field of LP gas systems, and who is

sufficiently familiar with applicable working

directives and accident prevention regulations,

as well as commonly accepted procedures of

this technology, all of the above enabling him

to evaluate, determine and assess the safe

operational state of LP gas systems.

Gas system

– Opening the shutoff valve (3) on the LP gas

cylinder (5) causes gas to flow through the gas

filter (13). At this point, possible contaminants

are trapped in a paper filter, and metallic par-

ticles from gas cylinder are removed by means

of a small magnet.

– Setting ignition key to Pos. 1 (ON) opens so-

lenoid valve (14), allowing LP gas to flow from

gas filter (13) into primary chamber of gas reg-

ulator (16). Here, a spring-loaded valve reduc-

es gas pressure to approximately 150 mbar

(2.2 psi).

– When starter begins to crank engine (10), a

vacuum is created in the suction channel.

Through vacuum line (11), this vacuum acts

on low-pressure diaphragm in secondary stage

of gas regulator. Diaphragm opens low-pres-

sure valve, and gas can be drawn into engine.

– Pressing choke button causes choke lifting

solenoid (17) to open low-pressure valve, al-

lowing gas to flow directly through carburetor

and into engine. This function is particularly

important in cold-starting situations. To pre-

vent high-level enrichment of intake mixture

with LP gas, choke button should not be

pressed for longer than 3-5 seconds.

Note:

The connection on cylinder shutoff valve (3)

must face straight up (extraction of LP gas

in gaseous state).

LP Gas Engine (HONDA GX 270)

Carburetor in LP gas operation (example)

1 Gas inlet

2 Air intake

3 Air/fuel mixture outlet

4 Mixing chamber

5 Gas jet

Gas regulator

– Engines using LP gas as a fuel are equipped

with a gas regulator which feeds LP gas to the

carburetor of a gasoline engine. The carbure-

tor generates an air/fuel mixture which is drawn

into the combustion chamber for ignition.

Note:

For information on other maintanance and

adjustments of the engine, refer to the Serv-

ice manual “4-Stroke Internal Combustion

Engines” (5.905-122).

12

Unit Functions KMR 1250 B, LPG, D

Diesel Engine (YANMAR L 70 AE-DE)

1 Drive shaft

2 Housing, engine

3 Piston

4 Cylinder head

5 Injector

6 Fuel feed line

7 Fuel line from fuel tank

8 Injection pump

9 Shim

10 Housing, injection pump

11 Cam shaft

Injection system

The injection pump (8) delivers fuel to the injec-

tor nozzle (5) via fuel line (6). The fuel, is then

injected into the combustion chamber above the

engine piston (3), where the extreme engine

compression causes the fuel to self-ignite.

Note:

For information on other maintenance and

adjustments of the engine, refer to the Serv-

ice manual „4-Stroke Internal Combustion

Engines“ (5.905-122).

6

1

2

3

4

5

7

8

11

10

9

13

KMR 1250 B, LPG, D Unit Functions

Diesel Engine (YANMAR L 70 AE-DE)

Injection pump (cross-section)

Injection pump

The injection cam on the camshaft shuttles the

injection pump piston (1) back and forth. Fuel is

conveyed to the injection nozzle via pressure

valve (7).

Injection timing is determined by the thickness

and number of shims (2) in shim pack.

Note:

Checking injection timing and related fine

adjustment are the exclusive domain of a

licensed service facility.

In the event that the injection pump fails to deliv-

er fuel, the entire injection pump assembly must

be removed and checked.

Note:

Injection pump service and repair are the

exclusive domain of a licensed service facil-

ity.

Injector assembly

The fuel that is conveyed to the injector by the

injection pump is transported through the feed

channel (14), past the nozzle valve (13), and then

sprayed into the engine combustion chamber.

Injector assembly (cross-section)

4

3

2

1

56

7

8

9

10

11

13

12

14

1 Pump piston

2 Shim pack

3 Flange

4 Fuel inlet

5 Pressure valve holder

6 Valve spring

7 Pressure valve

8 Housing, injection pump

9 Piston spring

10 Holder, piston spring

11 Housing, injector

12 Valve spring

13 Nozzle valve

14 Fuel feed line

14

Unit Functions KMR 1250 B, LPG, D

Steering and Drive Power

1 RH drive chain

2 Impeller fan

3 Drive belt, impeller fan

4 Drive belt, hydrostatic transmission

5 Hydrostatic transmission

6 LH drive chain

7 Brush roller

8 Drive belt, brush roller

9 Drive belt, LH side brush

(option)

10 LH side brush (option)

11 Chain, steering

12 RH side brush

13 Drive belt, brush roller

14 Drive belt, RH side brush

15 Steering wheel

MEngine

14 6

8

10

7

3

5

4

9

12

11

2

13

15

1

M

15

KMR 1250 B, LPG, D Unit Functions

1 Hydraulic unit

2 Engine B / LPG / D

3 Steering wheel

4 Operator seat

5 Debris container, raised

6 Impeller fan

7 Dust filter

Sweeping system

8 Rear wheel

9 Debris container, lowered

10 Hydrostatic transmission

11 Brush roller

12 Coarse-dirt flap

13 Front wheel

14 Side brush

4

2

1

14 13 12 11 10 9 8

6

7

5

3

16

Troubleshooting Information KMR 1250 B, LPG, D

Check fuse F1/F2

Fuse F2 protects the entire control voltage cir-

cuitry. This fuse is located on the A1 circuit board.

– Check fuse and replace as required.

A1 Circuit board

F1 Fuse, motor filter cleaning (10 A)

F2 Fuse, control voltage (7,5 A)

Check battery voltage

– Check battery voltage with voltmeter.

– Check electrolyte level on low-maintenance

battery.

– If required, recharge battery using external

battery charger (e.g., P/N 6.654-046).

Fuses F1/F2 on A1 circuit board

Fuse F4 in electrical box

Checking ignition switch S1 while removed from unit

Check fuse F4 and wiring

When the engine is running, the battery receives

a steady charge current from the alternator.

The fuse F4 (15 A rating) protects this circuit.

The fuse is located beneath the electrical box.

– Check fuse and replace as required.

– Check all wiring and connections between

alternator and battery.

Check ignition switch S1

– Remove screws on instrument panel (2), and

carefully lift off instrument panel.

– Check ignition switch (1) for continuity at its

various positions (0, 1, 2).

Key position Connection Function

0 30/1 - 15 Engine Stop

1 30 - 15/54 In operation

2 30 - 50 Starter

Starter Fails to Turn Engine

A1

F1

(10A)

F2

(7,5A)

F4

(15A)

F4 Fuse, generator

1 Ignition switch (S1)

2 Screws, instrument panel

3 Ignition switch, bottom view

1

2

30

15

50

30/1

3

15/54

(15/50)

17

KMR 1250 B, LPG, D Troubleshooting Information

Check voltage on starter solenoid

– Hold ignition switch in position II.

– Measure the voltage between solenoid ter-

minal and vehicle ground.

– If the meter fails to indicate a voltage, wiring

must be checked for possible defect.

– If a voltage is present but starter fails to turn,

starter is defective and must be replaced.

Note:

The connecting wiring for the starter sole-

noid are not shown in electrical diagram.

Checking voltage on starter motor M1

Checking voltage on starter solenoid

Check starter M1

– Hold ignition switch in position II.

– If a voltage is present but starter fails to turn,

starter is defective and must be replaced.

Starter Fails to Turn Engine

V

SW

V

18

Troubleshooting Information KMR 1250 B, LPG, D

Check regulator

ORIGINAL

When the engine is running, the alternator gener-

ates a continuous current flow. The regulator

automatically adapts this current as required

(depending on battery charge status and electri-

cal load).

– Start engine and allow to run.

– Using a clip-on ammeter, measure regulator

charging current on X1 plug coupling (white

wire on male connector or red wire on female

coupling of X1 connector).

If a charging current cannot be measured, this

indicates that the alternator is faulty and must be

replaced.

Checking regulator charging current

Starter Fails to Turn Engine

Checking regulator charging current

Check regulator

REVISED

Units of recent manufacture no longer feature

the X1 plug coupling. Wires are connected by

individual round plug couplings instead.

– Start engine and allow to run.

– Using a clip-on ammeter, measure regulator

charging current on red-and-white wire cou-

pling.

If a charging current cannot be measured, this

indicates that the alternator is faulty and must be

replaced.

ws White wire

rt Red wire

1 Plug coupling

2 Round male plug w/ female coupling

ws

rt

A

1

ws

rt

A

2

19

KMR 1250 B, LPG, D Troubleshooting Information

Checking S3 seat contact switch

Note:

Actuating the starter without a load on the

seat will crank the engine but not start it!

– Disconnect wire connections from seat con-

tact switch.

– Connect an ohmmeter to check seat contact

switch for continuity.

– With a physical load on the seat cushion, the

switch opens, and there is no continuity.

– In the absence of a physical load on the seat

cushion, switch contacts are closed.

– Adjust or replace seat contact switch as re-

quired.

Checking spark plug (gasoline & LPG engine)

Checking seat contact switch S3

Check spark plug

(gasoline and LPG engine)

– If ceramic insulator shows signs of break-

age of cracking, spark plug must be replaced.

– Heavily fouled spark plugs must be replaced.

– Using a feeler gauge, measure electrode gap,

and bend electrodes to adjust as required.

– To compress captive seal washer on new

spark plug, screw in plug hand-tight, then

tighten 1/2 turn. Tighten used spark plugs

only by 1/8 to 1/4 turn.

Check oil level switch S9

(gasoline and LPG engine)

In the event that the engine oil level drops down

too far, the oil level switch cuts out the ignition.

This causes the engine to stall and will prevent

engine restarts.

– Remove the terminal of the yellow wire.

– Using the ohmmeter, check the connecting

terminal for continuity.

– If the oil level is sufficiently high, there will be

no continuity.

– If the oil level is too low, there must be con-

tinuity.

– Top up engine oil or replace oil level switch

as required.

Checking oil level switch S9 (gasoline & LPG

engine)

Starter Turns Engine but Engine Fails to Start

- S3

0,70 - 0,80 mm

0.028 - 0.031 in.

20

Troubleshooting Information KMR 1250 B, LPG, D

Starter Turns Engine but Engine Fails to Start

Check compression release lever (diesel

engine)

– Engine is equipped with compression release

lever. During engine starting, it can be actu-

ated for a short while to ease overcoming

engine resistance at top dead center.

Note:

To enable engine to start with hood open,

seat contact switch must be jumpered.

Jumper must again be removed once en-

gine has started.

Fuel filter (diesel engine only)

Compression release lever (diesel engine)

4 2

1

3

5

6

7

Using Diesel fuel (diesel engine)

Exceptionally low outdoor temperatures may

cause diesel fuel to congeal. In this condition,

fuel is no longer supplied to the engine.

– To prevent this condition occurring, add vis-

cosity agents (winterized diesel fuel or dena-

tured alcohol) to the tank before cold weath-

er sets in.

– If the fuel congeals, replace fuel tank content

with winterized diesel fuel or add viscosity

agents.

– Continue by allowing the power sweeper to

warm up in a cold environment, with engine

idling.

1 Oil filler neck

2 Lever, compression release

3 Injector line

4 Injector

5 Tank filler cap

6 Seal ring

7 Fuel filter

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