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17

MS 780, MS 880

Condition

Cause

Remedy

Engine speed drops quickly under 
load – low power

Air filter dirty

Clean air filter or replace if 
necessary

Throttle shutter not opened fully

Check throttle cable and rod

Tank vent faulty

Replace tank vent

Fuel pickup body dirty

Install new pickup body

Fuel strainer dirty

Clean fuel strainer 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 necessary

Main jet bores or ports blocked

Clean the carburetor

Pump diaphragm damaged or 
fatigued

Fit new pump diaphragm 

Impulse hose damaged or kinked

Install new impulse hose

Ignition timing wrong, flywheel out 
of adjustment, key in flywheel has 
sheared off

Fit key if necessary and secure 
flywheel properly or install new 
flywheel

Содержание MS 880

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

Страница 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...

Страница 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...

Страница 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...

Страница 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...

Страница 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...

Страница 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...

Страница 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...

Страница 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...

Страница 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...

Страница 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...

Страница 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...

Страница 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...

Страница 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...

Страница 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...

Страница 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...

Страница 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...

Страница 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...

Страница 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...

Страница 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...

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

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