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3

MS 780, MS 880

1.

Introduction

This service manual contains 
detailed descriptions of all the repair 
and servicing procedures specific to 
this power tool.

You should make use of the 
illustrated parts lists while carrying 
out repair work. They show the 
installed positions of the individual 
components and assemblies.

Refer to the latest edition of the 
relevant parts list to check the part 
numbers of any replacement parts. 

A fault on the machine may have 
several causes. To help locate the 
fault, consult the chapter on 
"Troubleshooting" and the 
"STIHL Service Training System" 
for all assemblies.

Refer to the “Technical Information” 
bulletins for engineering changes 
which have been introduced since 
publication of this service manual. 
Technical information bulletins also 
supplement the parts list until a 
revised edition is issued.

The special tools mentioned in the 
descriptions are listed in the chapter 
on "Special Servicing Tools" in this 
manual. Use the part numbers to 
identify the tools in the 
"STIHL Special Tools" manual. The 
manual lists all special servicing 
tools currently available from 
STIHL.

Symbols are included in the text and 
pictures for greater clarity. 
The meanings are as follows:

In the descriptions:

:

= Action to be taken as 

shown in the illustration   
(above the text)

– = Action to be taken that is 

not shown in the illustration 
(above the text)

In the illustrations:

A

Pointer

a

Direction of movement

@

 4.2 = Reference to another

chapter, i.e. chapter 4.2 
in this example.

Service manuals and all technical 
information bulletins are intended 
exclusively for the use of properly 
equipped repair shops. They must 
not be passed to third parties.

Servicing and repairs are made 
considerably easier if the machine 
is mounted to assembly stand (3) 
5910 890 3100. To do this, secure 
the mounting plate (2) 
5910 850 1650 to the assembly 
stand with two screws (1) and 
washers. 

The screws must not project since 
they, depending on the machine, 
may damage housings when the 
machine is clamped in position.

The above operation is not 
necessary with the new assembly 
stand 5910 890 3101 since the 
mounting plate is already fitted.

1

2

3

219RA000 TG

Summary of Contents for MS 880

Page 1: ...STIH STIHL MS 780 880 2009 08...

Page 2: ...ion Timing 54 9 2 Ignition Module 54 9 2 1 Removing and Installing Version with two mounting screws 54 9 2 2 Removing and Installing Version with three mounting screws 56 9 3 Testing the Ignition Modu...

Page 3: ...the Carburetor Walbro Carburetor 105 14 6 1 Metering Diaphragm 105 14 6 2 Inlet Needle 106 14 6 3 Fixed Jet 107 14 6 4 Pump Diaphragm 107 14 6 5 Choke Shaft Choke Shutter 108 14 6 6 Throttle Shaft Th...

Page 4: ...bers to identify the tools in the STIHL Special Tools manual The manual lists all special servicing tools currently available from STIHL Symbols are included in the text and pictures for greater clari...

Page 5: ...re carrying out repairs or mounting the machine to the assembly stand Always use original STIHL replacement parts They can be identified by the STIHL part number the logo and the STIHL parts symbol K...

Page 6: ...rmed outdoors only Spilled fuel must be wiped away immediately Always perform leakage test after working on the fuel system and the engine Fuel system hose barb connectors Pull off or push on fuel hos...

Page 7: ...0 5 bar under vacuum 0 5 bar 0 5 bar 3 2 Fuel System Carburetor leakage test at gauge pressure 0 8 bar Operation of tank vent at gauge pressure 0 5 bar Fuel as in instruction manual 3 3 Ignition Syst...

Page 8: ...Cover spur gear crankcase 3 0 4 M 10x1 Decompression valve 14 0 Nut M 5 Filter cover twist lock 1 0 Nut M 5 Flange carburetor tank housing 5 0 Screw P 6x32 5 Handlebar right stiffener tank housing 8...

Page 9: ...0 Spark plug M 14x1 25 Spark plug 25 0 Screw M 5x25 Ignition module crankcase old MS 880 9 0 1 4 Screw M 5x20 Ignition module crankcase 8 0 5 Screw M 6x30 Cylinder crankcase 15 0 4 Remarks 1 Loctite...

Page 10: ...le speed too high Check carburetor settings and readjust properly if necessary Clutch springs stretched or fatigued Replace the clutch springs or install new clutch Clutch spring hooks broken Replace...

Page 11: ...n sprocket worn Fit new chain sprocket Saw chain stops under load at full throttle Clutch shoes badly worn Install new clutch Clutch drum badly worn Install new clutch drum Brake band does not release...

Page 12: ...p body Valve in oil tank blocked Clean or replace valve Spur gear broken Fit new spur gears Oil pump damaged or worn Install new oil pump Machine losing chain oil Oil pump body damaged Install new oil...

Page 13: ...almost without resistance crankshaft does not turn Guide pegs on pawls or pawls themselves are worn Fit new pawls Spring clip on pawl fatigued Fit new spring clip Spring clip installed wrong Install s...

Page 14: ...ixture too much oil Use correct mixture of fuel and oil Incorrect air gap between ignition module and flywheel Set air gap correctly Flywheel cracked or damaged or pole shoes have turned blue Install...

Page 15: ...Install new spark plug Faulty insulation or short in short circuit wire Check short circuit wire for short circuit to ground Break in ignition lead or insulation damaged Check ignition lead and repla...

Page 16: ...Fit a new metering diaphragm Metered diaphragm deformed Fit a new metering diaphragm Poor acceleration Air filter dirty Clean air filter or replace if necessary Setting of low speed screw too lean Che...

Page 17: ...ed Clean the carburetor Low speed screw too rich or too lean Reset low speed screw L correctly Setting of idle speed screw LA incorrect throttle shutter completely closed Reset idle speed screw LA cor...

Page 18: ...in carburetor replace if necessary Leak on fuel hose from tank to carburetor Seal connections or install new fuel hose Setting of high speed screw H too rich Check basic carburetor setting correct if...

Page 19: ...ver full power or runs erratically Piston rings worn or broken Fit new piston rings Muffler spark arresting screen carbonized Clean the muffler inlet and exhaust replace spark arresting screen replace...

Page 20: ...ip arrow Pull off the roller 1 1 2 3 165RA002 TG 1 216RA001 TG Hold the guide lug 1 steady and unscrew the nut 2 Unscrew the nuts arrows Remove the spiked bumper 3 Always use new self locking nuts Rea...

Page 21: ...BUY NOW Then Instant Download the Complete Manual Thank you very much...

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