Stiga RS100, RSC100 Workshop manual

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Page 1

RS100 - RSC100

WORKSHOP MANUAL

Rel. 0.0

The manufacturer reserves the right to make all the necessary technical or commercial improvements to

its products, so there may be some differences between the series of engines and the contents of this

manual. However the basic specifications and different operating procedures will remain the same.

by STIGA - No use of the illustrations or duplication, reproduction or translation, even partial, of the texts

in this document may be made without explicit authorization.

PRODUCTION YEAR

2018

IMPORTANT NOTICE : The information contained herein is intended for Service Operations and professionals only, able to competently perform the operations described herein, using the appropriate equipment in order to safeguard se-curity and performance of the machine. The manufacturer is not liable for damages or injuries arising from operations performed by individuals or inadequate facilities.

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Engine RS100 - RSC100

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CONTENTS

INTRODUCTION ..................................................................................................... 5

1. RULES AND PROCEDURES FOR SERVICE CENTRES .......................................... 6

1.1. Guarantee validity .................................................................................................................................6

1.2. Service repairs after guarantee period ................................................................................................6

1.3. Faultnotication ..................................................................................................................................... 6

1.4. Spare parts request ................................................................................................................................ 6

2. GENERAL AND SAFETY REGULATIONS ............................................................. 7

2.1. Qualicationofoperators .....................................................................................................................7

2.2. Safety measures ..................................................................................................................................... 7

2.3. Precautions during servicing ................................................................................................................. 7

2.4. Warning labels ........................................................................................................................................ 8

2.5. Necessary equipment ...........................................................................................................................8

2.6. Symbols and terms used for safety purposes ...................................................................................... 8

3. TECHNICAL DATA AND SPECIFICATIONS ........................................................ 9

3.1. Identication ........................................................................................................................................... 9

3.2. Technical data .......................................................................................................................................9

3.3. Adjustments ............................................................................................................................................9

3.4. Expendable materials ............................................................................................................................ 9

3.5. Limiti di utilizzo ........................................................................................................................................9

3.6. Tightening torques ................................................................................................................................ 10

3.7. Table of Tightening torques .................................................................................................................11

3.8. Identicationofengineunits ............................................................................................................... 12

4. ENGINE TUNING AND TESTING ...................................................................... 13

4.1. Operating guidelines ........................................................................................................................... 13

4.2. Engine tuning program ........................................................................................................................ 13

4.3. Functional test ......................................................................................................................................14

5. TANK AND SUPPLY .......................................................................................... 15

5.1. Emptying and removing the tank ....................................................................................................... 16

5.2. Cleaning the tank ................................................................................................................................16

5.3. Checking and cleaning the breather pipe ....................................................................................... 17

6. STARTING SYSTEM ........................................................................................... 18

6.1. Removing the starter assembly ..........................................................................................................18

6.2. Replacing the rope ..............................................................................................................................18

6.3. Replacing the hooks ............................................................................................................................ 19

7. INTAKE SYSTEM ............................................................................................... 20

7.1. Maintenanceandreplacementofthelterelement....................................................................... 20

7.1a. Maintenanceofspongelteringelement (

model RS100) ......................................................... 22

8. CARBURATION ( valid for RSC100 model) ................................................................ 23

8.1. Removing and cleaning the carburettor ........................................................................................... 23

8.2. Replacing the carburettor ................................................................................................................... 26

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Service manual

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Engine RS100 - RSC100

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CONTENTS

8.3. Adjusting minimum speed ..................................................................................................................26

8.4. Adjusting maximum speed ................................................................................................................. 26

8.5. Adjusting the carburation .................................................................................................................... 26

9. CARBURATION (

9.1. Removing and cleaning the carburettor ........................................................................................... 27

9.2. Replacing the carburettor ................................................................................................................... 30

9.3. Adjusting maximum speed ................................................................................................................. 30

9.4. Adjusting the carburation .................................................................................................................... 30

valid for RS100 model) ................................................................... 27

10. GOVERNOR SYSTEM OF THE CARBURETTOR ............................................... 31

10.1. Adjusting of a

10.2. Adjusting maximum speed (

10.2a. Adjusting maximum speed

10.3. Replacing the lever support ( model RSC100) ............................................................................. 35

10.3a. Replacing the lever support (

ccelerator cable ( model RSC100) .......................................................... 31

model RSC100) .............................................................................. 32

( model RS100) .........................................................................................34

model RS100) .............................................................................36

11. IGNITION ....................................................................................................... 37

11.1.Checkingtheefciencyoftheignitionsystem ................................................................................37

11.2. Adjusting the air gap and checking the coil ....................................................................................38

11.3. Replacing the coil ................................................................................................................................ 39

12. TURNING OFF AND STOPPING THE ENGINE ................................................ 40

12.1. Checking the control cable ................................................................................................................40

12.2.

Checking the system for turning off the engine ............................................................................................40

12.3. Checking the brake .............................................................................................................................41

12.4. Replacing the system for turning off and stopping the engine .......................................................42

13. EXHAUST SYSTEM .......................................................................................... 43

13.1.Removingandreplacingthemufer ................................................................................................. 43

14. ENGINE BLOCK - External operations ........................................................ 44

14.1. Checking the heating unit seal ..........................................................................................................44

14.2. Adjusting the valve clearance ...........................................................................................................45

14.3.

Dismantling and replacing the complete fan ................................................................................... 46

14.4. Blow-by check .....................................................................................................................................47

14.5. Replacing the upper compression ring of the engine shaft (fan side) ........................................... 47

14.6. Replacing the lower compression ring of the engine shaft (sump side) ........................................ 48

15. ENGINE BLOCK - Overhauling internal parts ............................................. 49

15.1. Removing the engine ..........................................................................................................................49

15.2. Carter opening ..................................................................................................................................... 50

15.3. Dismantling and checking the camshaft and counterweight governor ........................................ 51

15.4. Dismantling and checking the piston, piston rings, connecting rod and engine shaft ................ 53

15.5 Overhauling the valves .......................................................................................................................59

16. TROUBLESHOOTING ...................................................................................... 62

Service manual

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INTRODUCTION

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Engine RS100 - RSC100

The purpose of this manual is to provide to Service Centres the information necessary for a correct maintenance, dismantling and repair procedure for engines RS100 and RSC100. Interventions on the engine must be performed in accordance with instructions in the following pages and with safety regulations in force in the country in which the engine is operated, and only by authorised and appropriately trained personnel.

In every manual page the following informations are described:

C C

5. TANK AND SUPPLY

Service manual

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Engine RS100 - RSC100

5.1. Emptying and removing the tank

1 - Remove the ring (1) of the petrol pipe (2) from the tank side and drain all the fuel from the tank and the pipe into a suitable container.

2 - Remove the starter assembly (3) by loosening the three nuts (4).

3 - Loosen the rear screw (5) and remove the tank (6).

reverse.

WARNING: Before the tank with new

fuel, check that the petrol pipe is intact.

5.2. Cleaning the tank

[ 5.1].

1 - Remove the tank

2 - Remove the clamp (1) from the side of the tank and disconnect the petrol pipe (2).

air through it so as to remove any deposits inside.

4 - Keeping the hole (8) in the spigot closed, pour about 100 cc of clean petrol into the tank an d shake it vigorously to clean the inside.

ove operations in

7) and blow compressed

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EF D

Certain symbols are used in the manual, highlighting particularly important information, risks, warnings and prescriptions:

Warns of operations that should be carried

out with utmost care to avoid impairing the functionality and safety of the lawnmower.

Warns of operations that should be carried

out with utmost care to avoid injury to the operator.

 NOTE:Referstospecicadvicebythema-

nufacturer.

Reference to another procedure or part of

the manual.

Recommends that washers and O-rings are

checked and replaced if necessary.

Refers to use of special tools.

Shows all the operations requiring different

intervention methods depending on the engine version.

NOTE: During the description of procedures,

the indications “right”, “left”, “front”, “rear”, “upper” and “lower” refer to the engine mounted on the lawn tractor seen from the user’s perspective.

A: Motor typ for which the page is valid.

B: Reference to the chapter and the argument

with the relative numbering.

C: Presence of previous or following chapters from

the present chapter.

D: Issue date or possible audit.

E: Audit number.

F: Page progressive numbering.

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Please read all the contents of this manual to become familiar with the basics of the engine, which is fundamental for operating in a logical manner without making errors or wasting time.

Service manual

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1. RULES AND PROCEDURES FOR SERVICE CENTRES

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1.1. Guarantee validity

The warranty is supplied under the terms, procedures and limits stated in the contract.

1.2. Service repairs after guarantee period

The Service Centre must write a report for each intervention containing the serial number of the engine the problems complained of, the intervention made and possible spare parts used.. A copy of these reports must be kept and made available to the manufacturer together with the replaced parts, in case clients should make further complaints.

1.3. Faultnotication

The manufacturer should be informed of all faults that recur frequently; this allows it to carefully examine the problem and make corrections on the production line. Similarly, the manufacturer shall report any faults traced on its engines, indicating the best troubleshooting procedure.

[

3.1], and summary information about

Engine RS100 - RSC100

1.4. Spare parts request

When asking for spare parts, you must quote their code by referring to the exploded views corresponding to the year of manufacture reported on the nameplate

[

3.1].

Service manual

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2. GENERAL AND SAFETY REGULATIONS

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IMPORTANT: Before commencing with any

intervention, carefully read the information provided in the present manual, in particular the following safety regulations.

2.1. Qualicationofoperators

All maintenance, disassembly and repairs must be carried out by expert mechanics who are familiar with all the accident prevention and safety regulations after reading through the procedures in this manual.

2.2. Safety measures

All the engines are built in conformity with the European safety regulations in force. To maintain initial safety levels in the long term, the Service Centre should take proactive measures by making checks whenever possible. Every time you are asked to service the engine (or the lawnmower on which it is installed), you should:

• check:

- that the safety devices function correctly;

Engine RS100 - RSC100

regulations that apply to most repair shops, we recommend you:

- disconnect the spark plug cap before servicing;

- protect hands with suitable working gloves, especially when working near the cutting unit;

- check that you do not cause accidental petrol leaks or other losses;

- do not smoke when working on the tank or when handling petrol;

- do not inhale oil or petrol fumes;

- clean up all traces of spilt petrol immediately;

- do not pollute the environment with oil, petrol or other waste and dispose of all waste in accordance with the laws in force.

Exhaust gas contains carbon monoxide,

which is highly toxic, odourless and colourless. Avoid inhaling.

- Perform tests on the engine in a well-ventilated environment or in the presence of adequate exhaust gas extraction systems.

- that the casings and protection covers have not been removed;

- thatthenameplatesorspecicationlabelshave

not been removed or made illegible, (as they form an integral part of the safety devices).

• also:

- restore to proper working order any safety devices which have been manipulated or removed;

- replace ineffective, damaged or missing guards and covers;

- replace illegible labels;

- donotcarryoutoperationsormodicationson

the lawnmower or on the engine that could affect their performance or lead to an improper or different use from the one for which it has been designed and approved;

- warn the customer that the failure to comply with the above points automatically voids the warranty and the responsibility of the manufacturer.

2.3. Precautions during servicing

As well as following the usual accident prevention

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Service manual

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Engine RS100 - RSC100

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2. GENERAL AND SAFETY REGULATIONS

2.4. Warning labels

On the canopy motor, in a immediately identication position, are some indication or prescription plates for the safety operator. The plates are as follows:

1 2 3

RS100

1 - Fire hazard due to:

- Petrol or oil

Prevent by following the precautions below:

- Do not smoke or ignite a ame in the vicinity of

the petrol or oil;

- Turn engine off before adding petrol;

- Do not spill petrol on overheated or electric parts

of the engine;

- Handle or store petrol or oil in well-ventilated

areas;

- Use non-flammable oil for cleaning engine

parts.

฀••฀•••฀••••

XXX

readequate ventilation and, therefore, avoid gas poisoning.

4 - Motor label (see [ 3.1])

2.5. Necessary equipment

All the operations can be carried out with the tools normally used in a good garage.

The indicates that special tools or equipment are recommended.

2.6. Symbols and terms used for safety purposes

Some paragraphs in this manual are preceded by symbols which indicate the following:

, symbol used for certain interventions

Operations that should be carried out with ut-

most care to avoid impairing the functionality and safety of the engine and/or lawnmower on which it is installed.

Operations that should be carried out with

utmost care to avoid injury to operators.

-Accumulationofammablematerial

Prevent by following the precautions below:

- Remove dry leaves, chips, pieces of paper, dust or

other ammable material which has accumulated

in or is attached to the engine.

- Electrical cabling

Short circuits can cause res. Prevent by following

the precautions below:

- Always keep the electrical connections of the

machine clean and tightly sealed;

- Tighten any loose connectors or cabling clamps.

Replace those that are damaged.

2 - Observe the instructions and warnings contained in the present manual and on the safety plates on the engine.

Inappropriate functioning and maintenance can result in serious injury or even death.

3 - Ventilation of closed areas:

In the event that it is necessary to start the engine in a closed environment or if petrol or cleaning oil is being used, open doors and windows to ensu-

“WARNING” stresses the risk of injury to oneself and others if instructions and regulations are not observed.

Service manual

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Engine RS100 - RSC100

••฀•••฀••••

RS100

XXX

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3. TECHNICAL DATA AND SPECIFICATIONS

3.4. Expendable materials

RSC100 RS100

3.1. Identication

Every motor is marked with a serial number on the base and applied on the canopy; this serial number characters and can identify:

Year of

manufacture

Date

Daily progressive number

The serial number must be reported on every operating sheet in the warranty application and is fundamental for identifying and ordering spare parts.

Petrol

Engine oil

Spark plug

Starter rope ø 3x2350 mm

- da 5 a 35 °C

- da -15 a + 35°C

Unleaded (green)

minimum

GGP K7 RTC

90N.O.

SAE 30 10W30

3.5. Limiti di utilizzo

The following table gives the use limits of certain components subject to wear, after which the component must be replaced.

RSC100 RS100

Minimum inlet valve stem diameter

Minimum exhaust valve stem diameter

Minimum inlet valve head rim thicknesse

Minimum exhaust valve head rim thickness

5,45 mm

5,42 mm

0,6 mm

1,0 mm

3.2. Technical data

RSC100 RS100

Displacement 100 cc

Bore 58 mm

Stroke 37,8 mm

Compression ratio 8,5 : 1

Minimum speed

Maximum speed

Fuel tank capacity

Oil sump capacity

Dry weight

(SLOW) (

r.p.m.)1800 (±100)

(FAST) (r.p.m.)

2900 (±100) 2800 (±100)

0,85 litres

0,40 litres

7,80 kg

3.3. Adjustments

Distance between spark plug electrodes

Coil air gap 0,35 - 0,45 mm

0,6 - 0,8 mm

Minimum valve spring length 29,4 mm

Maximum gap between ends of cylinder rings

Max. axial gap for compression rings

Minimum gudgeon pin diameter

Max. gudgeon pin-piston seat diameter

Maximum connecting rod diameter

gudgeon pin side

crank side

0,8 mm

0,12 mm

11,95 mm

12,05 mm

24,07 mm

Inlet valve clearance 0,15 - 0,20 mm

Exhaust valve clearance 0,15 - 0,20 mm

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Service manual

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3.6. Tightening torques

6-8 Nm

8-10 Nm

8-12 Nm

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Mod. RSC 100

Engine RS100 - RSC100

3. TECHNICAL DATA AND SPECIFICATIONS

60-70 Nm

8-12 Nm

16-20 Nm

8-12 Nm

4-6 Nm

6-8 Nm

7-9 Nm 11-13 Nm

8-12 Nm

8-10 Nm

Mod. RS 100

7-9 Nm

8-10 Nm

Service manual

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Engine RS100 - RSC100

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3. TECHNICAL DATA AND SPECIFICATIONS

3.7. Table of Tightening torques

Chapter Ref. Description of screw Tightening torques

5 Assembly xing nut 8 - 10 Nm

5 Tank xing screw 8 - 10 Nm

6 Fixing nuts, starter assembly 8 - 10 Nm

6 Starter screw 4 - 6 Nm

8 - 9 Fixing nuts carburettor and lter 6 - 8 Nm

10 Support screw, governor assembly 8 - 12 Nm

11 - 14 Spark plug tightening torque 16 - 20 Nm

11 Fixing screw reel 8 - 12 Nm

11 Coil xing stud 8 - 12 Nm

12 Brake support screws 8 - 12 Nm

13 Mufer xing nuts 8 - 10 Nm

13 Mufer xing screw 8 - 10 Nm

14 Screws valve cover 7 - 9 Nm

14 Fan xing nut 60 - 70 Nm

14 Blow-by closure plate screw 7 - 9 Nm

15 Union screws under carter and sump 8 - 12 Nm

15 Counterweight governor xing screw 8 - 12 Nm

15 Fixing screws lower connecting rod cap 11 - 13 Nm

P.S. For the coupling tourque of all standard screws refer to the single table.

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Service manual

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Engine RS100 - RSC100

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3. TECHNICAL DATA AND SPECIFICATIONS

3.8. Identicationofengineunits

For ease of reference, this manual has subdivided maintenance operations into different sections, each of which refers to an engine component unit as indicated in the diagrams below.

Mod. RSC 100

Mod. RS 100

Ignition

Carburettor

Turning off and Stopping

Tank and Supply

Air intake

Carburation control

Starting system

Exhaust system

Engine block

Ignition

Carburettor

Turning off and Stopping

Air intake

Tank and Supply

Carburation control

Starting system

Exhaust system

Engine block

Service manual

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Engine RS100 - RSC100

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4. ENGINE TUNING AND TESTING

4.1. Operating guidelines

The engine requires a series of interventions (shown in the table below) in order to ensure minimum basic maintenance.

Operation First 5 hours

Check oil level

Change oil *

Clean mufer and engine

Check air cleaner *

Replace air cleaner *

Check spark plug

Replace spark plug

(1)

Replace the oil every 25 hours if the engine is working at full load or at high temperatures.

(2)

Clean the air lter more often if the machine is working in dusty areas.

(1)

(2)

- ■ - - -

■ - - ■ -

- ■ - - -

- - ■ - -

- ■ - - -

- - - ■ -

For the operations that are not difcult for the nal

user the assistance centre must maintain the mo-

tor in perfect efciency, in accordance with two

intervention lines:

- Tuning the engine whenever possible.

- Recommending the client a routine maintenance program at set intervals (e.g. at the end of the season or before a long period of inactivity).

Every 5 hours

or daily

- adjusting minimum [ 8.3] and maximum speeds

adjusting maximum speeds

RS100)

inspecting the condition of the spark plug; checking the distance between the electrodes

[ 11.1];

- tightening the screws [ 15.2];

Every 25

hours or

every season

[ 10.2] ( RSC100)

;

Every 50

hours or

every season

[ 10.2a] (

Every 100

hours

4.2. Engine tuning program

As part of general engine tuning or any intervention on the lawn tractor, it is recommended that the Service Centre performs a series of operations aimed

at maintaining the engine’s efciency.

Tuning should involve:

- external blowing and cleaning the cylinder

head, cylinder and mufer by removing any

remains of grass and mud;

- checking the oil level, topping up or replacing parts if necessary

inspecting the condition of the starter rope and

checking that it functions correctly

;

[

6.2];

- cleaning and oiling the air lter [ 7.1] e [

7.1a];

- emptying and cleaning the fuel tank and checking the breather pipe [ 5.2];

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functional test [ 4.3].

Should the checks and adjustments fail to achieve a satisfactory result, refer to chapter

[ 16] for

troubleshooting.

Service manual

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4. ENGINE TUNING AND TESTING

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4.3. Functional test

A functional test needs to be carried out at the end of each servicing operation, to check that the operations made are effective. The test must be performed in compliance with the safety regulations regarding the use of the lawnmower on which the engine is installed.

The functional test is carried out as follows:

a. Refuelling and checking the supply system

When you have refuelled the tank with new petrol, check the seal of the tank, the cap and the carburettor pipe.

Engine RS100 - RSC100

b. Cold starting test (

With the throttle control in “CHOKE”, start the engine a few times to check it runs normally.

c. Check the engine rpm

When the engine is hot enough, check the engine speed with the throttle control set to “SLOW” and

” ( RSC100)

“FAST

to the specications

d. Hot start test

With the engine hot and the throttle control set to “SLOW” ( RSC100), start the engine a few times to check it runs normally.

If all of these operations have a positive result, the engine can be considered fully serviceable and be returned to the client.

RSC100)

; the readings should be equal

[ 3.2].

Service manual

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Engine RS100 - RSC100

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5. TANK AND SUPPLY

IMPORTANT: Carefully read the information below before commencing any intervention.

General Information

The fuel supply system comprise the bottom of the tank prevents deposits and impurities from reaching the carburettor.

The tank is equipped with a lter, located at the bottom of the tank, which prevents deposits and impurities

from reaching the carburettor.

The supply to the carburettor o

tank as the engine runs is compensated by a breather pipe in the cap.

s the petrol tank connected to the carburettor by a pipe; a mesh lter at

at chamber is caused by gravity and the volume of petrol taken from the

See the relevant section supply system.

WARNING: All interventions on the supply system must be performed in safe conditions, therefore:

- do not smoke;

- always empty the tank;

- work in a ventilated env

- collect any remaining petrol by positioning a suitable container under the engine, avoiding soiling the work bench;

- remove all traces of spilt petrol immediately;

- check you have connected the pipes before pouring petrol back into the tank.

[

16] for advice on resolving problems due to the malfunctioning of the petrol

ironmentawayfromnakedamesorunprotectedsourcesofheat;

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Service manual

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Engine RS100 - RSC100

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5. TANK AND SUPPLY

5.1. Emptying and removing the tank

1 - Remove the ring (1) of the petrol pipe (2) from the tank side and drain all the fuel from the tank and the pipe into a suitable container.

2 - Remove the starter assembly (3) by loosening the three nuts (4).

3 - Loosen the rear screw (5) and remove the tank (6).

4 - When tting, perform the ab

reverse.

WARNING:Beforerellingthetankwithnew

fuel, check that the petrol pipe is intact.

ove operations in

Service manual

5.2. Cleaning the tank

1 - Remove the tank

2 - Remove the clamp (1) from the side of the tank and disconnect the petrol pipe (2).

3 - Slide out the lter tube (7) and blow compressed air through it so as to remove any deposits inside.

4 - Keeping the hole (8) in the spigot closed, pour about 100 cc of clean petrol into the tank and shake it vigorously to clean the inside.

page 16

[

5.1].

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Engine RS100 - RSC100

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5. TANK AND SUPPLY

5 - Empty the tank and dispose of the petrol used for cleaning in accordance with the laws in force.

6 - Ret the tank

(5) to the torques indicated.

7 - Replace the starter assembly by securing the nuts (4) at the specied torque.

WARNING: Beforerellingthetankwithnew

fuel, check that the petrol pipe is intact.

[ 5.1] tightening the screws

5.3. Checking and cleaning the breather pipe

1 - Remove the cap (9) and pull out the gasket (10) and the sponge (11).

2 - Check that:

- the gasket (10) is intact and without cracks or

ssures;

- the air passages (12) inside the cap are not clogged;

- the sponge (11) is not crushed or broken.

NOTE: Always replace the entire cap if the

gasket or sponge is damaged.

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Tightening torques

Assembly xing nut 8-10 Nm

5 Tank xing screw 8-10 Nm

Service manual

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Engine RS100 - RSC100

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6. STARTING SYSTEM

General information

The starte pulley to the fan (and therefore to the engine shaft) is transmitted through a pair of couplings. The return of the pulley and the rewinding of the rope are obtained from a spiral spring.

r assembly inside the cover consists of a rope wound around a pulley. The movement from the

See the releva ting system.

nt section [

16] for advice on resolving problems due to the malfunctioning of the star-

6.1. Removing the starter assembly

1 - To get access to the starter assembly (1), the cover (2) must be removed by unscrewing the three nuts (3).

2 - Ret the starter assembly (1) by tightening the cover nuts (3) to the torque indicated.

6.2. Replacing the rope

1 - Remove the starter assembly

2 - Keep hold of the pulley (4) and slowly unwind (clockwise) the entire rope (5) to gradually release the return spring. If the rope breaks, the spring will be already released and you will only have to unwind the rope.

3 - Undo or cut the knot at the end of the rope (5) and remove the section still attached to the pulley.

[

6.1].

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Engine RS100 - RSC100

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6. STARTING SYSTEM

4 - Rotate the pulley (4) through about 6 complete turns anticlockwise in order to load the spring and

hold it still.

5 - Insert one end of the rope (5) (ø 3mm - length 2350mm) through the gui into the hole in the pulley (4), and fasten it by tying a knot.

6 - Insert the other end of the rope into the grip (6), fasten it with a knot and carefully release the pulley to allow the rope to rewind itself completely onto the pulley.

7 - Check that the pulley rotates freely.

8 - After pulling the entire length of the rope, check that the pulley (4) is able to complete another 2-3 turns before compressing the spring.

de in the ventilation grille,

9 - Ret the starter assembly

6.3. Replacing the hooks

1 - Remove the starter assembly

2 - Loosen the screw (7) and remove the cover (8), putting the spring to one side. Be careful not to slip the pulley (4) off its seat.

3 - Remove the couplings (9) and take out the springs (10) from their seats.

NOTE: Always replace the complete set

consisting of hooks, return springs, cover and screw, as a unit.

4 - When tting, tighten the screw (7) to the torque indicated.

5 - Ret the starter assembly

[ 6.1].

[

6.1].

Release 00 - 03/2018

page 19

NOTE: Check that the spring lever (10) is

outside the coupling (9).

Tightening torques

Fixing nuts, starter assembly

7 Starter screw 4-6 Nm

Technical information

Starter rope dimensions ø 3x2350 mm

Service manual

8-10 Nm

Page 20

Engine RS100 - RSC100

<< BACK >>

7. INTAKE SYSTEM

General information

The intake system uses an air lter directly connected to the carburettor by means of a manifold which conveys the air/petrol mixture to the inlet valve.

See the relevant section intake system.

Aninefcientltercanletdustordebrisenterthecylinder,causingprematureweartothepistonringsand

cylinder.

The air lter is found on the left hand side of the engine and can be inspected without having to remove

other parts.

The lter assembly is to be removed only to accede the carburettor.

[

16] for advice on resolving problems due to the malfunctioning of the air

7.1. Maintenanceand replacement of the lter

element

WARNING: Never run the engine without air

lter.Theenginewouldcertainlybedamaged.

1 - Clean the area around the lter cover (1) by blowing it with compressed air.

2 - Remove the cover (1) by pressing on the upper tab (2).

WARNING: Close the intake duct to prevent

theentryofforeignobjects(seegure).

3 - Remove the lter eleme

4 - Check carefully that the element has no holes

or tears, and replace it, if damaged.

nt (3).

Service manual

page 20

Release 00 - 03/2018

Page 21

7. INTAKE SYSTEM

<< BACK >>

Engine RS100 - RSC100

5 - element on a hard surface so as to remove excess dirt, and blow it through with compressed air, outwards from the inside. Replace the element if it is too dirty.

6 nance referred to in the paragraph

Cartridgelterelement: Bang the air lter

Spongelterelement: Perform the mainte-

[ 7.1a].

7 - Ret the element (3) and the cover (1) into their

housings, into its housing, paying attentio up the clips correctly (2).

8 -

sponge lter element, make sure it is properly positioned between the tabs, as shown in the gure.

model RS100 During the installation of the

n to hook

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page 21

Service manual

Page 22

7. INTAKE SYSTEM

<< BACK >>

7.1a. Maintenanceofspongelteringelement ( model RS100)

Engine RS100 - RSC100

1 - Remove the cover [ lter element (1).

WARNING: Close the intake duct to prevent

the entry of foreign objects.

2 - Check carefully that the element has no holes or tears, and replace it, if d

 WARNING:Thelterelementmustbekept

clean and oil soaked and must be replaced if broken, cut or if it is crumbling. Donot usecompressedairtocleanthelterelement.

3 - Wash the lter element with water and detergent

and dry with a clean cloth.

7.1] and remove the

amaged.

4 - Pour two spoons of clean motor oil onto the element and wring the sponge repeatedly until the oil is evenly spread.

5 - Remove any excess oil with a clean cloth.

6 - Replace the lter element as shown in points 6

and 7 of the paragraph

[ 7.1].

Service manual

page 22

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Page 23

8. CARBURATION ( valid for RSC100 model)

<< BACK >>

General information The carburettor has a oat with a xed jet and a “CHOKE” control.

Engine RS100 - RSC100

See the relevant section

The carburettor is located on the left-hand side of the engine. For maintenance operations it is necessary

to dismantle the air intake lter in the sequence shown below.

Dismantle the engine from the machine following the instructions in section

[

16] for advice on resolving problems due to carburation.

WARNING! All operations on the tank and

supply system must be carried out in safe conditions, so:

- do not smoke;

- always empty the tank if petrol is not strictly

necessary for the operation to be carried out;

- work in a ventilated environment away from

nakedamesorunprotectedsourcesofheat;

- collect petrol in a suitable container with a cap

using a funnel and avoid spilling it on the work bench;

[ 15.1].

- remove all traces of spilt petrol immediately;

- check you have connected the pipes before

pouring petrol back into the tank.

8.1. Removing and cleaning the carburettor

1 - Remove the lter element

2 - Unscrew the two nuts (1) holding the lter carrier

(2) to the engine and remove it. Pull off the breather tube (3).

3 - Remove the clamp (4) for the petrol pipe (5) from the side of the carburettor and use a suitable container to collect all the petrol in the pipe.

4 - Remove the gasket (6) and bring the intake throttle rod to a minimum, pulling out the carburettor.

[

7.1].

Release 00 - 03/2018

page 23

Service manual

Page 24

Engine RS100 - RSC100

<< BACK >>

8. CARBURATION ( valid for RSC100 model)

5 - Using pliers, disconnect the intake buttery rod

(7) and slide the small rod (8) for the relative compensation spring upwards.

6 - Disconnect the wire (9) from the choke buttery lever, completely remove the carburettor (10) for the relative compensatio

n spring upwards (11).

NOTE: Empty any remaining petrol from the

tank by removing the drain screw (12) as

showninthegure.Whennished,replace

the screw.

7 - Unscrew the central screw (13) securing the tank (14) and remove the corresponding OR (15).

Service manual

page 24

Release 00 - 03/2018

Page 25

<< BACK >>

Engine RS100 - RSC100

8. CARBURATION ( valid for RSC100 model)

8 - Pull out the pin (16), dismount the oat (17) and remove the gasket (18).

9 - Undo the main jet (19) and pull out the pilot jet (20).

10 - Check that no impurities or dirt are deposited in the seat of the needle (21) and of the pilot jet.

Make sure the rubber tip of the needle and the

oatarenotmarkedorworn.Iftheyare,replace

them.

11 - Clean the carburettor (10) the main jet (19) and the pilot jet (20) thoroughly by immersing them in clean petrol (or a detergent) for 24 hours. Dry with compressed air, blowing well through the carburettor holes.

12 - Mount the carburettor following the previous points 8, 7 and 6 in reverse order, remembering that:

It is always advisable to replace the washer

(18) and the O-Ring (15) of the oat chamber;

- the oat (17) must oscillate freely on the pin (16);

- the jet (19) should never be modied or replaced

with others even if they seem to have the same

specications;

- the choke (22) must open and close regularly;

- the screw (12) to drain the tank should be facing

the front of the engine.

13 - Remount the tie rods (7), (8) and (9) checking that the governor system moves smoothly without stopping.

14 re-mounting the carburettor onto the engine.

Always replace washers (6) and (11) when

Release 00 - 03/2018

page 25

15 - Fit the lter and tighten the relative nuts (1) to the torque indicated. Ret the lter element

7.1].

Service manual

[

Page 26

Engine RS100 - RSC100

<< BACK >>

8. CARBURATION ( valid for RSC100 model)

8.2. Replacing the carburettor

1 - Perform operations 1 - 2 - 3 - 4 - 5 - 6 - 12 - 13 - 14

- 15 indicated in section

[

8.1] above.

SLOW

8.3. Adjusting minimum speed

1 - Check that the throttle cable is adjusted cor-

[

rectly

10.1].

2 - Let the engine heat up for a few minutes, then set the throttle control to “SLOW”.

Check the rotation speed on the speed indi-

cator (23).

NOTE: The engine’s minimum speed must be

between 1800 (±100) rpm.

3 - Turn the screw (24) until you achieve a stable minimum speed within the above values.

8.4. Adjusting maximum speed

Service manual

page 26

NOTE: This operation is carried out by adju-

sting the governor system

[ 10.2].

8.5. Adjusting the carburation

NOTE: The carburation is set in the factory

and does not normally need changing. In the event of irregular functioning, clean the carburettor as indicated in section

[ 8.1].

Tightening torques

1 Carburettor nuts/lter 6-8 Nm

Technical information

Minimum speed (SLOW) 1800 (±100) g/1’

Special equipment

23 Speed indicator

Release 00 - 03/2018

Page 27

9. CARBURATION ( valid for RS100 model)

<< BACK >>

General information The carburettor is a xed jet oating type with “PRIMER”.

Engine RS100 - RSC100

See the rele

The carburettor is located on the left-hand side of the engine. For maintenance operations it is necessary

to dismantle the air intake lter in the sequence shown below.

Dismantle the engine from the machine following the instructions in section

vant section [

16] for advice on resolving problems due to carburation.

[ 15.1].

WARNING! All operations on the tank and

supply system must be carried out in safe conditions, so:

- do not smoke;

- always empty the tank if petrol is not strictly

necessary for the operation to be carried out;

- work in a ventilated environment away from

nakedamesorunprotectedsourcesofheat;

- collect petrol in a suitable container with a cap

using a funnel and avoid spilling it on the work bench;

- remove all traces of spilt petrol immediately;

- check you have connected the pipes before

pouring petrol back into the tank.

9.1. Removing and cleaning the carburettor

1 - Remove the lter element

2 - Remove the two nuts (1) securing the lter hol-

der (2).

3 - Remove the lter holder (2), disconnecting the vent pipe and paying attention to the “PRIMER” pipe.

4 - Remove the clamp (3) and the “PRIMER” pipe (4). Use a suitable container to collect all the petrol in the pipe.

5 - Remove the gasket (5) and bring the intake throttle rod to a minimum, pulling out the carburettor.

[

7.1].

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page 27

Service manual

Page 28

Engine RS100 - RSC100

<< BACK >>

9. CARBURATION ( valid for RS100 model)

6 - Using pliers, disconnect the intake buttery rod

(6) and slide the small rod (7) for the relative compensation spring up

7 - Completely remove the carburettor (8) and the gasket (9).

wards.

NOTE: Empty any remaining petrol from the

tank by removing the drain screw (10) as

showninthegure.Whennished,replace

the screw.

Service manual

page 28

8 - Unscrew the central screw (11) securing the tank (12) and remove the corresponding OR (13).

Release 00 - 03/2018

Page 29

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Engine RS100 - RSC100

9. CARBURATION ( valid for RS100 model)

9 - Pull out the pin (14), dismount the oat (15) and remove the gasket (16).

10 - Undo the main jet (17) and pull out the pilot jet (18).

11 - Check that no impurities or dirt are deposited in the seat of the needle (17) and of the pilot jet.

Make sure the rubber tip of the needle and the

oatarenotmarkedorworn.Iftheyare,replace

them.

12 - Clean the carburettor (8) the main jet (17) and the pilot jet (18) thoroughly by immersing them in clean petrol (or a detergent) for 24 hours. Dry with compressed air, blowing well through the carburettor holes.

13 - Mount the carburettor following the previous points 9, 8 and 7 in reverse order, remembering that:

It is always advisable to replace the washer

(16) and the O-Ring (13) of the oat chamber;

- the oat (15) must oscillate freely on the pin (14);

- the jet (17) should never be modied or replaced

with others even if th

specications;

- the screw (10) to drain the tank should be facing

the front of the engine.

14 - Remount the tie ro that the governor system moves smoothly without stopping.

15 re-mounting the carburettor onto the engine.

16 - Fit the lter and tighten the relative nuts (1) to the torque indicated. Ret the lter element

7.1]

Always replace washers (5) and (9) when

ey seem to have the same

ds (6) and (7) checking

[

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page 29

Service manual

Page 30

Engine RS100 - RSC100

<< BACK >>

9. CARBURATION ( valid for RS100 model)

9.2. Replacing the carburettor

1 - Perform operations 1 - 2 - 3 - 4 - 5 - 6 - 7 - 13 - 14

- 15 - 16 indicated in section

9.3. Adjusting maximum speed

NOTE: This operation is carried out by adju-

sting the governor system

9.4. Adjusting the carburation

[

9.1] above.

[ 10.2a].

NOTE: The carburation is set in the factory

and does not normally need changing. In the event of irregular functioning, clean the carburettor as indicated in section

Tightening torques

1 Carburettor nuts/lter 6-8 Nm

[ 9.1].

Service manual

page 30

Release 00 - 03/2018

Page 31

Engine RS100 - RSC100

<< BACK >>

10. GOVERNOR SYSTEM OF THE CARBURETTOR

General information

The carburettor governor system uses a engine shaft linkage tted on a support xed to the left-hand side of the engine, completed by a counterweight device, driven by the camshaft, and thus sensitive to changes in the engine’s revolution pattern depending on load.

The force of the counterweights, transferred to the control lever, tends to shut the main carburettor butter-

y, in opposition with the spring that would keep it open; the balance between the spring loading and the thrust of the counterweights on the control lever modies the buttery opening and adapts the ow of fuel

to the engine so that the revolution speed is kept constant with engine load changes.

See the relevant section

[

16] for advice on resolving problems related to the governor system.

10.1. Adjusting of a

ccelerator cable (

model

RSC100)

1 - Remove the lter holder

[

8.1].

2 - Loosen the screw (1) of the clamp (2) so that the cable casing (3) is free to move.

3 - Set the throttle control lever (4) to “CHOKE”.

CHOKE

Release 00 - 03/2018

4 - Move governor control lever (5) forward as far as possible and, by keeping it in this position, lock the casing (3) full tightening the screw (1) of the clamp (2).

page 31

Service manual

Page 32

Engine RS100 - RSC100

<< BACK >>

10. GOVERNOR SYSTEM OF THE CARBURETTOR

10.2. Adjusting maximum speed ( model RSC100)

1 - Check that the throttle cable is adjusted correctly

[

10.1].

FAST

2 - Let the engine heat up for a few minutes then set the throttle control to “FAST”.

3 -

Check the rotation speed on the speed

indicator (6).

4 - Bend the plate (7) slightly upwards using pliers to increase the engine RPM and downwards to decrease it.

5 - Check by moving the lever to the “SLOW” position and then to the “FAST” position to eliminate

any slack. Check the RPM again using the engine speed indicator.

Make sure the accelerator is in the “FAST” position and check the air lever rod is not already activated or in contact.

Service manual

NOTE: The engine’s maximum speed must be

between 2900 (±100) rpm; if you do not read

this value, proceed as follows.

6 - Check:

- that the spring (8) is intact and that it is properly positioned in its seat;

- that the wire (9) and th

e relative spring (10) are

intact and not deformed;

- that the moving levers (11) are not bent or deformed and replace the entire support if necessary

[ 10.3].

page 32

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Page 33

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Engine RS100 - RSC100

10. GOVERNOR SYSTEM OF THE CARBURETTOR

7 - If the above checks do not show any faults, the phasing of the governor’s control lever (12) with respect to the counterweight device must be

checked:

- stop the engine and move the accelerator control to “FAST”;

- slacken off the control lever (13) locknut (12);

- without changing the lever (12) position determined by the spring (10) and tie-engine shaft (9), use a screwdriver to turn pin (14) clockwise to the end of its stroke and then lock the nut (13).

Release 00 - 03/2018

page 33

Service manual

Page 34

Engine RS100 - RSC100

<< BACK >>

10. GOVERNOR SYSTEM OF THE CARBURETTOR

10.2a. Adjusting maximum speed

RS100)

1 - Check the rotation speed on the speed

tor (5).

indica

2 - Bend the plate (6) slightly upwards using pliers to increase the engine RPM and downwards to decrease it.

NOTE: The engine’s maximum speed must be

between 2800 (±100) rpm; if you do not read

this value, proceed as follows.

( model

3 - Check:

- that the spring (7) is intact and that it is properly positioned in its seat;

- that the wire (8) and the relative spring (9) are intact and not deformed;

4 - If the above checks do not show any faults, the phasing of the governor’s control lever (10) with respect to the counterweight device must be checked:

- stop the engine and make sure that the lever (10) is in the end run position;

- slacken off the control l

- without changing the lever (10) position determined by the spring (9) and tie-engine shaft (8), use a screwdriver to turn pin (12) clockwise to the end of its stroke and then lock the nut (11).

ever (11) locknut (10);

Service manual

page 34

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Page 35

Engine RS100 - RSC100

<< BACK >>

10. GOVERNOR SYSTEM OF THE CARBURETTOR

10.3. Replacing the lever support ( model

RSC100)

1 - Remove the lter element lter holder

2 - Position the choke lever to minimum (“SLOW” position).

3 - Disconnect the accelerator cable (3) and the spring (8).

4 - Loosen the two screws (15) securing the support (16) to the engine and the clip (17) securing the petrol pipe.

5 - Turn the lever support and remove the tie-rod (18) on the starter throttle lever (CHOKE).

[ 8.1].

[

7.1] and the

6 - Perform the above operations in reverse order when assembling.

7 - Replace the lter holder

element

8 - Adjust the maximum speed

Tightening torques

Technical information

Maximum speed (FAST)

Special equipment

6 Speed indicator

[ 7.1].

Support screw, governor assembly

[ 8.1] and the lter

[ 10.2].

8-12 Nm

2900 (±100) g/1’

Release 00 - 03/2018

page 35

Service manual

Page 36

<< BACK >>

Engine RS100 - RSC100

10. GOVERNOR SYSTEM OF THE CARBURETTOR

10.3a. Replacing the lever support ( model

RS100)

1 -

Remove the lter element [

lter holder

2 - Disconnect the spring (7).

[ 9.1].

7.1] and the

3 - Remove the two screws (13) and replace the lever support.

4 - Perform the ab when assembling.

7 -

Replace the lter holder [ 9.1] and the lter

element

8 - Adjust the maximum speed

Tightening torques

Technical information

Maximum speed

Special equipment

5 Speed indicator

[ 7.1].

Support screw, governor assembly

ove operations in reverse order

[ 10.2a].

8-12 Nm

2800 (±100) g/1’

Service manual

page 36

Release 00 - 03/2018

Page 37

Engine RS100 - RSC100

<< BACK >>

11. IGNITION

General information

The ignition system has a fan with an electronic coil which supplies high voltage to the spark plug

See the relevant section [

The coil and complete fan are accessible by removing the cowl.

Dismount the engine from the machine by following the instructions in section

16] for advice on resolving problems related to the ignition.

0,6 - 0,8 mm

11.1. Checking the efficiency of the ignition

system

1 - Dismount the spark plug (1) and look at the colour on the end of the thread. This can give you a good idea of the carburation:

- black: mixture too greasy due to clogged air

lter;

- nut brown: regular carburation.

Replace the spark plug (with one of the same or equivalent characteristics) if the electrodes (2) are burnt or if the porcelain is broken or cracked.

[ 15.1].

FIRE HAZARD:

- do not check the ignition system if the spark

plug is not screwed in place;

spark test.

2 cap (4) and to earth on the engine (5). Activate the starter and see in the instrument if the spark jumps.

3 - If the test has a positive result, clean the electrodes (2) with compressed air and adjust the distance to 0.6-0.8 mm. Remount the spark plug and tighten

it to the specied levels.

Unless otherwise required, proceed to verify system components as indicated in section

 always use the specic toolfor the

Connect the tester (3) to the spark plug

11.2].

[

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page 37

Service manual

Page 38

11. IGNITION

<< BACK >>

Engine RS100 - RSC100

11.2. Adjusting the air gap and checking the coil

1 - Remove the starter assembly

2 - Make sure that the earth cable faston (6) of the coil (7) is not oxidized; if it is, disconnect, clean and remount it, spraying it with a special antioxidant.

3 - Check that the coil earth cable is intact. The black spark plug cable (8) should not have any cracks or signs of deterioration or burns which re-

duce its efciency and insulation level.

4 - Slack off the screw (9) and the stud (10) which secure the coil (7). At the bottom of the machine to which the engine

is tted, release the safety brake.

Rotate the fan (11) so as to bring the magnetic inserts next to the poles of the core of the coil.

[

6.1].

5 - Insert a 0.35 mm thickness gauge (12) between the complete fan (11) and the coil poles (7), push the coil until the poles come in contact with the thickness gauge and secure screw (9) and stud

0,35÷0,45 mm

(10); with the ywheel locked, the airgap must be between 0.35 and 0.45 mm.

 NOTE: An accurate inspection of the ef-

ciency of a coil can only be carried out in a

laboratory equipped with a oscilloscope.

To make a brief check, proceed as follows:

6 - Disconnect the earth cable faston (6) of the coi (7).

Service manual

page 38

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Page 39

<< BACK >>

11. IGNITION

7 - Perform a spark test as indicated in [ 11.1].

- If the spark jumps: the coil functions properly and in the event of malfunction, verify that the cut-off cable (13) is not earthed.

- if the spark does not jump: the coil is faulty and must be replaced

Engine RS100 - RSC100

[ 11.3].

8 - Ret the starter assembly

11.3. Replacing the coil

1 - Remove the starter assembly [

2 - Disconnect the faston of the earth cable (6).

3 - Undo the screw (9) and the stud (10) and remove the coil (7).

4 - Mount the new coil and regulate the air gap according to the procedure indicated in points 4 and 5 in section

5 - Connect the faston of the earth cable (6).

[ 11.2].

[ 6.1].

6.1].

Release 00 - 03/2018

page 39

6 - Ret the starter assembly

Tightening torques

1 Spark plug tightening torque 16-20 Nm

Coil xing screw 8-12 Nm

Coil xing stud 8-12 Nm

Technical information

Type of spark plug GGP K7 RTC

Distance between electrodes 0,6-0,8 mm

Air gap/fan 0,35-0,45 mm

Special equipment

3 Tester for spark test

[ 6.1].

Service manual

Page 40

Engine RS100 - RSC100

<< BACK >>

12. TURNING OFF AND STOPPING THE ENGINE

General information

The engine is turned off and stopped by releasing a lever on the lawnmower. The cable acts on a lever which simultaneously activates a microswitch that sends the coil to earth as well as a brake which acts on

the ywheel.

The brake must be able to stop the engine within 3 seconds after it is turned off.

To solve problems in the system for turning off and stopping the engine, see the relevant chapter

To get access to the system for turning off and stopping the engine, remove the starter assembly.

12.1. Checking the control cable

1 - Remove the starter assembly

2 - Remove the lter assembly

RSC100 (or

3 - Check that the sheath (1) is not bent, that the wire (2) is securely connected to both the lawnmower lever and the lever (3) on the engine and that the terminal (4) is correctly fastened to the support (5).

4 - Check that the wire (2) runs freely inside the sheath (1) when you move the lever.

5 - Check that the end of the wire (2) is slightly loose when you release the lawnmower lever.

[ 9.1] mod. RS100).

[

[ 8.1] mod.

[

6.1].

16].

Service manual

6 - Ret the lter assembly [ 8.1] mod.

RSC100 (or

7 - Ret the starter assembly

12.2.

1 - Disconnect the coil Faston connector (6).

2 make contact with the leads on the points indica-

ted in the gure.

The instrument should read:

- ∞ = microswitch press

- 0 = microswitch free (lever released);

Otherwise, replace the system for turning off and stopping the engine.

page 40

[ 9.1] mod. RS100).

[ 6.1].

Checking the system for turning off the engine

Using a multimeter (7) as an ohmmeter,

ed (lever pulled);

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Engine RS100 - RSC100

<< BACK >>

12. TURNING OFF AND STOPPING THE ENGINE

12.3. Checking the brake

1 - Remove the starter assembly

[

6.1].

2 - Check that the thickness of the friction pad (8) is not less than 2 mm at its thinnest point.

3 - Make sure that the control lever (5) moves freely and remove any remains of grass and mud.

4 - Ret the starter assembly

5 - Start the engine, release the lawnmower lever and check that the engine stops within 3 seconds.

6 - If it stops after 3 seconds, replace the entire assembly friction pad are not capable of ensuring compliance with braking times.

[ 12.4], because the spring or the

WARNING! Never return the lawnmower to

yourclientwithoutcheckingbrakeefcien-

cy.

[ 6.1].

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Service manual

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Engine RS100 - RSC100

<< BACK >>

12. TURNING OFF AND STOPPING THE ENGINE

12.4. Replacing the system for turning off and stop-

ping the engine

1 - Remove the starter assembly

[ 6.1].

2 - Remove the lter assembly

RSC100 (or

3 - Disconnect the brake (3).

4 - Disconnect the earth cable Faston connector (9).

5 - Loosen the two screws (10) and the spring (11). Remove the support bracket (5).

6 - When tting, perform the above operations in

reverse, tightening the s indicated.

7 - Ret the starter assembly assembly

mod. RS100).

[ 9.1] mod. RS100).

[ 8.1] mod. RSC100 (or [ 9.1]

[ 8.1] mod.

wire (2) from the lever

crews (10) to the torque

[ 6.1] and the lter

8 - Start the engine, release the lawnmower lever and check that the engine stops within 3 seconds.

Tightening torques

10 Brake support screws

Special equipment

7 Universal tester

8-12 Nm

Service manual

page 42

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Engine RS100 - RSC100

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13. EXHAUST SYSTEM

General information

The exhaust system consists of a mufer installed on the cylinder together with a gasket, a spacer and a heatproof bafe.

To solve problems in the exhaust system, see the relevant chapter

13.1. Removingandreplacingthemufer

1 - Remove the two nuts (1) and the screw (2) that

x the guard (3) and the mufer.

2 - Take out the mufer (4) and the heatproof bafe

(5).

[

16].

3 - On assembly:

- thoroughly clean the cylinder contact surface,

removing all deposits or fragments on the hea-

tproof bafe;

- always replace damaged mufers;

- always replace the heatproof bafe (5) if it is

broken or cracked;

- tighten the two nuts (1) and the screw (2) to the

specied levels.

Tightening torques

1 Mufer xing nuts

2 Mufer xing screw 8-10 Nm

8-10 Nm

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Engine RS100 - RSC100

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14. ENGINE BLOCK - External operations

14.1. Checking the heating unit seal

1 - Remove the cap (1) and take o plug (2).

2 - Manually set the piston to the TDC (Top Dead Centre) of the compression stroke so that both valves are closed.

3 sting tool (3) into the spark plug hole and connect the supply pipe to a compressed air socket with a pressure of approximately 4 bar (58 psi).

4 - On opening the air tap (4), the manometer gauge on the engine side should position itself in the green zone and remain there for about 30 seconds. If the gauge falls rapidly it means that the compression is poor.

Screw the terminal of the compression te-

ut the spark

NOTE: Lack of compression could be due

to:

- incorrect valve clearance [ 14.2];

lack of seal in the valves [

piston rings worn [

5 - Ret the spark plug (2) and close it to the indi- cated couple.

15.4].

15.5];

Service manual

page 44

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Engine RS100 - RSC100

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14. ENGINE BLOCK - External operations

14.2. Adjusting the valve clearance

WARNING: The adjustment must be made

with the engine is cold.

1 - Remove the cover and demount the spark plug

[

14.1].

2 - Remove lid (5) which is secured with three screws (6) and remove the washer (7).

3 - Manually set the piston to the TDC (Top Dead Centre) of the compression stroke so that both valves are closed.

4 - Use a feeler gauge (8) to check the gap between the rocker arm and the tip of the valve stem; the gauge should pass between without forcing and without a further g

5 - Slack is adjusted by loosening the dowel (9) and suitably adjusting the register nut (10) to obtain the following values:

ap.

Inlet - IN = 0,15 - 0,20 mm Exhaust - EX = 0,15 - 0,20 mm

6 - Following adjustment, check that the pushrods (11) are properly inserted in the rocker arm (12) and always fully tighten the dowel (9).

7 - When reassembling check the condition of the gasket (7) of the cover (5) and replace it if it is damaged. Tighten the screws (6) to the torque indicated.

8 - Assemble the spark plug [ 14.1].

housings

0,15÷0,20 mm

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Service manual

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Engine RS100 - RSC100

14. ENGINE BLOCK - External operations

14.3.

Dismantling and replacing the complete fan

1 - Remove the starter assembly

2 - Operate the exhaust brake.

3 - Using an airgun, un

4 - Undo the screw (14) and the stud (15) and remove the electronic coil (16).

5 complete fan (17) as in

Ensure that the engine shaft key is retained.

Using a suitable extraction tool, remove the

do the nut (13).

dicated in the diagram.

[

6.1].

 NOTE:Ifitisdifculttodisassemblethefan,

use a hammer and hit the extractor screw.

6 - When tting the complete fan check that the key

(18) is in good condition and replace it, if deformed. Close the nut (13) to the indicated couple.

7 - Ret the coil (14), tightening the screw (15) and the stud (16) to the torque indicated.

8 -

Readjust the airgap until it is correct [ 11.2].

9 - Ret the starter assembly [ 6.1].

Service manual

page 46

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Engine RS100 - RSC100

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14. ENGINE BLOCK - External operations

14.4. Blow-by check

1 - Remove the complete fan

2 - Unscrew the screw (19) xing the closing plate (20).

3 - Check that the reed (21) is not blocked or deformed. Replace if this is the case. If necessary wash with water and neutral detergents.

4 ret the closure plate (20), tightening the screw to the torque indicated.

5 - Ret the complete fan

If necessary, replace the gasket (22) and

[

14.3].

[ 14.3].

14.5. Replacing the upper compression ring of the

engine shaft (fan side)

1 - Remove the complete fan

2 - Take out the spline key (18).

3 - Use a thin screwdriver inserted under the sealing lip to extract the oil seal ring (23).

4 - The new ring (24) must be inserted with the help of a pipe (25) with a diameter of approximately 35-40 mm, taking care not to damage the sealing lip.

5 - Ret the key (18) and the complete fan

14.3]

[

14.3].

[

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Engine RS100 - RSC100

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14. ENGINE BLOCK - External operations

14.6. Replacing the lower compression ring of the

engine shaft (sump side)

NOTE - Before executing this operation di-

scharge all the oil from the bowl and rotate

180° the motor.

1 - Remove the blade (26) and hub (27).

2 - Take out the spline key (28).

3 - Use a thin screwdriver inserted under the sealing lip to extract the oil seal ring (29).

4 - Make a paper tube (30) around the shaft to protect the sealing lip and insert the new ring (31) so that it enters its housing.

5 - Complete the insertion with the help of a pipe (32) of a diameter of approximately 30-35 mm.

Service manual

page 48

Tightening torques

2 Spark plug tightening torque

6 Valve cover xing screws 7-9 Nm

13 Fan xing nut 60-70 Nm

19 Blow-by closure plate screw 7-9 Nm

Technical information

Inlet valve clearance

Exhaust valve clearance 0,15-0,20 mm

Special equipment

3 Compression testing tool

Release 00 - 03/2018

16-20 Nm

0,15-0,20 mm

Page 49

Engine RS100 - RSC100

<< BACK >>

15. ENGINE BLOCK - Overhauling internal parts

15.1. Removing the engine

1 - Empty the tank of fuel [ 5.1].

2 - Drain the oil in the sump by removing the ller

plug and turning the mower on its side.

3 - Disconnect the engine brake cable (1) and the

throttle cable (2) (

4 - Remove the blade assembly and undo the three screws (3) which are accessible from the bottom of the lawnmower.

RSC100).

Grasp the engine at points which offer a secure grip, taking account of the overall weight given in the relevant table

[ 3.2].

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15. ENGINE BLOCK - Overhauling internal parts

All the following operations on the grass cutter necessitate the removal of the motor.

15.2. Carter opening

1 - ( RSC100 model only) Remove the carburettor

[ 10.3].

2 - Loosen the lever xing nut (4), release the spring (5) and remove the control lever.

3 - Position the engine on a stable support and remove the sparkplug. Bring the piston to the TDC (Top Dead Centre).

4 - Turn the engine upside down and place it with the shaft pointing upwards.

5 - Loosen the seven screws (6) and remove the engine sump with the help of levers in the two points indicated.

6 - verify the phasing between the engine shaft and the camshaft;

If necessary, re-set the phasing, referring to the indications provided.

[ 8.1] and remove the lever support

7 - On assembly, follow the steps described in reverse and:

- clean the contact surfaces, removing any remaining silicone;

- evenly distribute the silicone seal (THREE BOND

1207) (7) as shown in the gure;

- ensure that the two centring pins (8) are properly inserted;

- always sump side

- close the screws (6) intersection lock bowl to the indicated couple;

8 - After installing the engine on the machine:

- rell the sump and make sure that the ller plug

is tight.

check the adjustment of the brake cable

12.1]

model only).

9 - Following reassembly it is advisable to check the engine’s peak rpm

10.2a] ( RS100) .

replace the compression ring from the

[ 14.6].

and the throttle cable

[ 10.2] ( RSC100) [

[ 10.1] ( RSC100

[

Service manual

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Engine RS100 - RSC100

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15. ENGINE BLOCK - Overhauling internal parts

15.3. Dismantling and checking the camshaft and

counterweight governor

1 - Bring the piston to the TDC (Top Dead Centre).

(EX)

(IN)

2 - Open the crank case

3 - Remove the camshaft (9).

4 for wear and tear. Th than 11,95 mm.

5 - Measure the cams (IN and EX) on the camshaft, checking for wear. The value must not be lower than 24,10 mm (IN) and 24,13 mm (EX).

6 - Check the regular movement of the pressure reducer (10) and the efciency of the spring (11); the whole group must always be replaced in the case of breakage or irregular operation of the pressure reducer.

Measure seat (A) of the camshaft, checking

[

15.2].

e value must not be lower

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7 - Check that the irregolar centrifugal (12) that are not present ruptures of the lubrication pallets.

8 - Turn the governor’s gears quickly and check that the counterweights (13) expand correctly, causing the pin (14) to be moved axially.

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Engine RS100 - RSC100

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15. ENGINE BLOCK - Overhauling internal parts

9 - In the case of breakage or irregular operation

of the counterweights the whole group, xed by a

plate (15) and a screw (16) must be replaced.

10 - When installing the new unit, take care to position the washer (17) correctly on the opposite side.

11 - Before tting the camshaft ensure that the two

tappets (18) are correctly housed in their seats.

12 - When retting the camshaft, maximum care

must be taken to match up the two references (19) and (20) punched on the gears, so as to ensure correct distribution phasing.

13 - During assembly, refer to the operations in section place the washer (7) between the sump and the housing.

[ 15.2] always remembering to re-

Service manual

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Engine RS100 - RSC100

15. ENGINE BLOCK - Overhauling internal parts

15.4. Dismantling and checking the piston, piston

rings, connecting rod and engine shaft

NOTA - These paragraphs describe all the

operations for checking and overhauling the thermal components of the engine; it is left to the operator to assess the advisability of performing all the operations described or

only part of them, depending on the type of engine problems encountered.

1 - Remove the engine from the machine

15.1]

2 - Remove the complete fan

3 - Open the cover

4 - Remove the camshaft

5- Dismantle the connecting rod (21) cap (22), xed with two screws (23) (take note of any reference

marks for retting).

6 - Push the connecting rod (22) so as to ensure the piston (24) enters the cylinder (25) fully.

7 - Pull the engine shaft (26) out completely.

8 - To remove the piston (24) pull the connecting rod (22) as shown in the gure.

[ 15.2].

[ 14.3].

[ 15.3].

[

Release 00 - 03/2018

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9 move the two compression rings and the oil scraper ring from the piston (24).

10 - Carefully remove all carbon deposits from the compression rings, the inside of the cylinder and the piston head.

Use the special expanding tool (27) to re-

Service manual

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Engine RS100 - RSC100

15. ENGINE BLOCK - Overhauling internal parts

9 - To check the wear in the compression rings, insert them one at a time into the cylinder (25) by about 10-15 mm and measure the gap between the two ends with a feeler gauge (28); the rings must be replaced if the gap is more than 0.8 mm.

NOTE - If a gap of more than 0.4 mm is measu-

10 - Use a section of an old ring (29) to carefully clean the inside of the piston (24) ring housings, ensuring that the oil passage holes are not blocked.

red with new rings it means that the cylinder is worn beyond the acceptable limits and must be replaced. The cylinder must be replaced if it shows striping due to a seizure.

11 - To check the wear in the piston ring housings,

t a new ring and measure the residual space with

a feeler gauge (30). The piston must be replaced if it is greater than 0.12 mm in the two compression ring housings.

12 - Use a screwdriver to remove the clamping ring (31) and remove the gudgeon pin (32) from the piston (24).

Service manual

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Engine RS100 - RSC100

15. ENGINE BLOCK - Overhauling internal parts

13 - Check the diameter of the gudgeon pin (32) in several places and replace it if it is less than 11.95 mm, even at a single point.

14 - Check the diameters of the gudgeon pin housings (A) on the piston (24) and replace the piston if they are more than 12.05 mm, even at a single point.

15 - Fit the cap (21) to the connecting rod (22) and

check the diameter from the gudgeon pin side and the crank side; replace the connecting rod if the values are greater than:

B : 12,05 mm on the gudgeon pin side; C : 24,07 mm on the crank side.

If the connecting engine shaft is outside measurement tolerances or has small scratches or marks, it is necessary to replace it.

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Engine RS100 - RSC100

15. ENGINE BLOCK - Overhauling internal parts

16 - On the engine shaft (26), removed beforehand, use a digital gauge to check the diameter of the connecting rod pin. The value must not be less than 23.92 mm or the

engine shaft will have to b

e replaced.

NOTE - In the case of seizing, the manifolds

canbepolishedwithneemerycloth,only

removing foreign matter and checking that thenalsizeremainswithintheaforementioned limit.

17 - To check the alignment between the manifolds and the protruding part of the shaft, place the engine shaft on two prismatic guides (33) and, with the help of a comparator (34) placed at the end, check the displacement by rotating the shaft. The shaft must be replaced if the displacement exceeds 0.10 mm.

IMPORTANT: A bent shaft must never be re-

paired!

WARNING - DANGER: A bent shaft causes ab-

normal vibrations and could be dangerous when the machine is used!

18 - To ret the rings to the piston, rst t the three

oil scraper rings (35), then the ring with a round edge (36) and nally the ring with a sharp edge (37), being careful over the markings (which must face the piston head) and in arranging the gaps to ensure that they are not aligned with each other;

Service manual

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15. ENGINE BLOCK - Overhauling internal parts

19 - Fit the connecting rod (22), gudgeon pin (32) and clamping rings (31) to the piston (2

NOTE - The marking on the piston must be

directed towards the intake.

The connecting rod must be mounted with

the marking (38) facing upwards.

4).

20 - Put the piston into the ring compression tool (39).

21 - Oil the inside of the piston liberally and insert the piston, with the marking facing the exhaust.

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15. ENGINE BLOCK - Overhauling internal parts

22 - Mount the engine shaft (26) and the connecting rod cap (21) with the relative screws (23), taking care with the position references (38) so as to avoid inverting the mounting direction of the cap.

Close the screws (23) to the indicated couple.

23 - After having xed the connecting rod cap, take

the greatest care to ensure that the two position references (19) and (20) punched on the engine shaft and camshaft gears, coincide, ensuring the correct distribution phasing.

24 - Close the carter and x the screws (6) to the indicated couple

25 - Whenever the engine shaft is dismantled and

retted, it is always necessary to:

- replace the sealing ring on the fan side

;

14.5]

[ 15.2].

[

Service manual

page 58

- replace the sealing ring on the sump side

14.6]

26 - During assembly perform the operations indicated in section to replace the silicone gasket (7) between the sump and the casing

[ 15.2] always remember

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[

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Engine RS100 - RSC100

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15. ENGINE BLOCK - Overhauling internal parts

15.5 Overhauling the valves

NOTE - These paragraphs describe all the

operations for checking and overhauling the valves;

1 - Remove the starter assembly [

2 - Open the crank case the piston

3 - Move the rocker arms (40); press down the spring seal cap (41) and move it sideways to remove from the valve stem (42).

IMPORTANT - The intake and exhaust valves are of different sizes.

4 - Use an emery cloth to remove all incrustations from the valve head and check the thickness of the rim (A); the valve must b is less than 0,6 mm or if it shows signs of burning.

lity of performing all the operations described or only part of them, depending on the type of engine problems encountered.

6.1].

[ 15.2] and remove

[ 15.4].

e replaced if the margin (A)

it is left to the operator to assess the advisabi-

5 - Check the diameter of stem (B) in several points and replace the valve if it is less than the following, even if only in one point:

5,45 mm (inlet - IN) 5,42 mm (exhaust - EX)

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15. ENGINE BLOCK - Overhauling internal parts

6 - Check the free length of the spring (43) and replace the spring of it is less than 29,4 mm.

7 - When mounting:

- carefully clean the v any foreign body;

- apply a lm of oil on the valve stems before inserting them in their respective housings;

- ensure the proper position of the intake valve and exhaust valve, which can be notice by the different sizes (Intake: larger, Exhaust: smaller).

8 - Replace the intake valves and check that the oil seal (44) is in place.

alve guides and housings of

Service manual

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15. ENGINE BLOCK - Overhauling internal parts

9 - Close the carter and x the screws (6) to the indicated couple

[ 15.2].

10 indicated in section

to replace the silicone gasket (7) between the sump and the casing.

11 - Ret the starter assembly

Tightening torques

Technical information

Oil sump capacity 0,40 litri

Diameter aspiration cam 24.1 mm

Diameter discharge cam 24,13 mm

Maximum segments gap in the cylinder 0,8 mm

Max. compression ring axial gap

Minimum gudgeon pin diameter 11,95 mm

Max. gudgeon pin housing diameter on piston

Max. connecting rod diameter

Diam. connecting rod’s pin on engine shaft

Verify the engine shaft extremes 0,10 mm

Minimum inlet valve stem diameter 5,45 mm

Minimum exhaust valve stem diameter 5,42 mm

Valve head margin min. thickness 0,6 mm

Minimum valve spring length 29,4 mm

Special equipment

40 Piston ring compressing tool

During assembly perform the operations

[ 15.2] always remember

[ 6.1].

Union screws under carter and sump

Counterweight governor xing screw

Fixing screws lower connecting rod cap

gudgeon pin side

crank side 24,07 mm

Piston ring removal expander

8-12 Nm

11-13 Nm

0,12 mm

12,05 mm

23,92 mm

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16. TROUBLESHOOTING

PROBLEM CAUSE SOLUTION

The engine does not start or

starts badly

The engine brake cable is faulty or unfastened

The OFF microswitch is faulty

Coil earth connection

Earth wire is attened

The coil is faulty and does not supply current or the air gap is too large

Carburettor dirty

Poor seal of carburettor needle valve

Choke blocked /not closed (

RSC100)

Adjust and/or replace the cable

[

12.1]

Replace the whole shut-down group

[

12.2]

Check electrical cabling of earth wire

[

11.1]

Replace the whole shut-down group

[ 12.4]

Check coil

Check and clean the carburettor

[

[ 9.1] ( RS100)

and

Clean the carburettor housing and needle valve [ 8.1] ( RSC100)

[ 9.1] ( RS100) or repla-

and ce the carburettor RSC100) and

Check and clean the carburettor and the choke

[ 11.2]

8.1] ( RSC100)

[ 8.2] (

[ 9.2] ( RS100)

[

8.1]

Startingisdifcultandstrains

the rope

The spark plug is badly connected or faulty

Blocked air lter

Valve malfunction

Insufcient pressure

The Primer is faulty ( RS100)

Presence of oil in the combustion chamber

Pressure reducer fault

Check spark spark plug

Execute the lter cleaning

and [ 7.1a] ( only for RS100)

Check the valve clearance

[

14.2]

Check tightness of cylinder head screws, replace washer if necessary. Check wear and tear of the piston

[

rings

Check the effective operation of the Primer

Clean the combustion chamber

Check the pressure reducer and counterweights

15.4]

11.1] or replace

[

15.3]

[ 7.1]

Service manual

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16. TROUBLESHOOTING

PROBLEM CAUSE SOLUTION

The engine starts but does

not run

Theengineisinefcientor

the runs irregularly

The tank cap has a clogged breather pipe

Insufcient pressure

Exhaust is blocked

The throttle cable is not well adjusted

RSC100)

(

The governor malfunctions or there is a problem with the rods

Air seepage in the carburettor

Carburettor dirty

Insufcient pressure

Clean and/or replace the cap

[

5.3];

Check correct valve operation [

Check that the spark plug is

15.5]

secured cracks in the casing. Ch tear of the piston rings

Check that there is airow through

the exhaust system and replace if necessary

Check and/or adjust the throttle cable [ 10.1]

Check the entire governor system

[ 10]

Replace the carburettor gaskets

[ 8.1] ( RSC100)

and

Check and clean the carburettor

[ 8.1] ( RSC100)

and

Check correct valve operation [

15.5]

secured cracks in the casing. tear of the piston rings

[ 11.1].

[

[ 9.1] ( RS100)

Check that the spark plug is

[ 11.1].

Check for any

eck wear and

[ 15.4]

13.1]

Check for any

Check wear and

[ 15.4]

The engine overreved

The engine judders

The coil air gap has been poorly adjusted

Oxidation or loosening of spark plug connections

Governor blocked due to breakage of centrifugal assembly or breakage of external governor springs. It is possible that the governor is dirty

Engine screws loose Tighten the screws

Engine shaft off-centre

Engine timing faulty

Adjust the air gap the problem persists, replace the coil

[ 11.3]

Perform spark test place spark plug

Check the entire governor system

[

10 and 15]

Replace the engine shaft

Check wear and tear of the connecting rod of the engine shaft, replace shaft if necessary

11.2] and if

[

[ 11.1] or re-

[ 15.4]

[

15.4]

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Engine RS100 - RSC100

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16. TROUBLESHOOTING

PROBLEM CAUSE SOLUTION

The engine does not turn off

The engine does not stop

within 3 seconds after it has

turned off

The engine uses a lot of oil

The engine brake cable is bent or jammed

The earth cable is disconnected or broken

Faulty or no clutch lining

Faulty blow-by operation

Poor piston ring seal

Excessive gap between the guide and the inlet valve stem

Ring assembly error

Check and/or adjust the cable

[

12.1]

Check and/or replace oil breather

[

tab

Replace the engine stopping system

[ 12.4]

Check and/or replace the blow-by system

dition of the air lter

Replace the rings

Check and/or replace the valve

[

Check the assembly of the rings

[

15.5]

15.4]

11.1]

14.4]. Check the con- [ 7.1]

15.4]

[

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Service manual