Stihl MS 18, MS 170 Servise Manual

Setup and Service Procedures for the

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MS 170, MS 180 Chain Saw

Introduction

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 The MS 170, MS 180 chain saw has a 2-cycle engine  STIHL assigns a 4 digit series number to every product  The MS 170, MS 180 is assigned the 1130 series number

 The 1130 series of saw was introduced to the market in

1995 as an 017, and then in 1998 the 018 was added

 In 2002 the model designation changed from 017 to MS

170, and 018 to MS 180

Specifications

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MS 170 MS 180

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 Engine Displacement 30.1 cc (1.8 cu.in) 31.8 cc(1.9 cu. in.)  Engine Power 1.3 kW (1.7bhp) 1.5kW (2.0 bhp)  Weight 3.9 kg (8.6 lbs) 4.0 kg (8.8 lbs.)  Fuel Capacity 250 cc (8.5 oz.)  Chain Oil Capacity 145 cc (4.9 oz.)  Recommended OILOMATIC® Chain 3/8” PMM3  Guide Bar Lengths Available 12” to 16”

 Engine Idle Speed 2800 RPM  Wide Open Throttle 14,000 RPM (with bar and chain installed)

Become Familiar With the Controls

Master Control Lever™

A single lever

operating the choke, throttle lock and on-off switch

0 = Off I = Ignition on Warm Start

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Cold Start

Starting Features

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The MS 170 is equipped with a

standard starter mechanism, and with 2 bar nuts holding the bar in place

The MS 180 C-B has the

Toolless Quick Chain Adjuster (QCA) for fast and easy chain and bar install and adjustment

The MS 180 C-BE also has the

Easy2Start™ starter mechanism which allows starting with less effort at a lower cranking speed

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Starting Features

The MS 180 C-B has the standard starter mechanism, which

requires a brisk pull on the rope to it’s full extension to start the engine

The MS 180 C-BE has the Easy2Start™ starter mechanism,

which allows starting by simply pulling out the rope slow and easy, winding the auxiliary spring which then spins the motor over to start it

Notice that the MS

180 C-BE has a deeper recoil

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housing and the handle extends out slightly farther for clearance

4

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Kickback!!!

Kickback occurs when the moving saw chain near the upper quadrant of the bar nose contacts a solid object or is pinched

The greater the force of the kickback reaction, the more difficult it becomes for the operator to control the saw

Chain and Bar Color Code Marking

 STIHL saw chain will have a green

or yellow tie strap to indicate if the chain is low-kickback or other than low-kickback

 The bar will have two green or

yellow dots on the powerhead end of the bar to identify if the bar is a reduced kickback bar or not

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Install the Bar and Chain

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 STIHL recommends the use of reduced

kickback bars and low kickback chains on all STIHL chain saws

 Yellow bar and chain combinations are for

trained professionals with extraordinary cutting needs

 Be sure the bar and chain are within the

recommended length for the model of saw being assembled

 Always wear gloves when handling saw

chain to protect your hands from the sharp cutters

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Install Bar & Chain: Quick Chain Adjuster

 Install the tensioning gear and fasten the screw securely  The bar can be installed with the STIHL logo facing up or

down; periodically the bar should be flipped to spread the wear over both edges of the bar

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Install Bar & Chain

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 Make sure the cutters on top of the bar are facing away from

the powerhead!

WRONG

CORRECT

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Quick Chain Adjuster (QCA)

 The QCA allows the user to adjust the

chain tension without tools

Loosen the wing nut

Rotate the

adjusting wheel

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Tighten the wing nut

Install Bar & Chain

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 If the saw does not have a QCA simply remove the 2 bar nuts,

install the bar and chain, making sure the adjusting pin is in the hole in the bar

Install Bar & Chain

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 Install the cover and the 2 nuts leaving them just snug against

the cover

Chain Adjustment

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The 1130 saws have a front

chain tensioner

Most STIHL chain saws have a

side chain tensioner that is more convenient to use

Saws come with a combination

wrench, commonly referred to as a “Scrench”, to make bar and chain service easy to do

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Install Bar & Chain

 Adjust the chain tension with the “Scrench” by holding up on

the nose of the bar, tightening the chain tension screw, then tightening the nuts

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Correct Chain Tension

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 With the chain brake

disengaged, pull the chain through from the top side and it should rotate freely without any slack appearing

 If the chain goes from

tight to loose the sprocket and chain may not be of the same pitch, or the sprocket and chain may have excessive wear and no longer have the same pitch

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Correct Chain Tension

 Regardless of bar

length, check for correct chain tension by pulling up on the chain at the center of the bar

 The tension is correct

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when the bottom of the drive link will just clear the bar groove

Cutterless Chain for Service

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 For any chain saw, to properly tune the carb or verify running

RPM at idle and wide open throttle a bar and chain should be installed

 Cutterless chains are available to provide a safe way for the

service technician to do this without fear of the chain coming into contact with anything

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Chain Brake

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All Current Models of STIHL Chain Saws are Equipped with the STIHL Quickstop® Chain Braking System

The chain is stopped and locked when the hand guard is

pushed toward the guide bar nose by the left hand – or when the brake is activated by enough inertia in certain kickback situations

Brake

Band

Engaged

Disengaged

Starting the 1130 Saw

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 Fill the tank with 89

octane brand name fuel with STIHL two-stroke oil mixed at a 50:1 ratio, or use STIHL MotoMix

 Add bar oil to the oil tank

for chain lubrication

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Starting the 1130 Saw

Push down on the interlock

on the top of the handle and then squeeze the throttle all the way open and hold it

Place the Master Control

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Lever™ in the full choke position, down to the #1 position

Instruction Manual Directions for Safely

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Starting a Chain Saw

(Never Drop Start a Chain Saw!)

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First Time Start-Up

 When the engine starts, commonly referred

to as a “false start”, move the Master Control Lever™ up to #2, to open the choke and then pull the rope again

 The engine should start and run at fast idle  Quickly “blip” the throttle to release the

engine from the fast idle position

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First Time Start-Up

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 If a saw is left in the fast idle position with the chain brake

engaged for even a very short period of time it may overheat the clutch and chain brake components and possibly ruin the tank housing as well

 To stop the engine raise the Master Control Lever™ to the 0

(off) position, #4 in the picture

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First Time Start-Up: Warm Up

 After the engine has started and the chain brake has been

released, slowly squeeze the throttle about half way open and then slowly release it back to idle

 Do this several times, for at least 20 seconds, to completely

purge any remaining air from the carburetor circuits and to allow the chain lubrication pump time to prime the system with bar and chain oil

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 Never allow any chain saw engine to run at full throttle without

a load, regardless if it is new or broken-in, for more than a few seconds

Bar & Chain Oiler Check

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Carefully hold the

tip of the bar over a piece of wood or cardboard

Run the saw at half

throttle and verify that a line of bar and chain lubricant is being slung off the end of the bar

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Factory Testing of All STIHL Products

 Every engine manufactured by STIHL has been started and

operated in a test cell

 The test cell makes carburetor adjustments and verifies

that the engine runs properly at idle, acceleration, and at full throttle under load

 The test cell measures the running performance and

emissions and verifies that they are within acceptable parameters

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 All the dealer needs to do is service the unit and verify it is

ready for the customer to operate it

 It is extremely rare that a new unit will need any major

adjustments or repair

Fault Analysis: STIHL Engine Check

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 When a unit is running poorly or not at all, using a systematic

approach to identify any and all faults present will allow the Service Technician to quickly and efficiently determine what is wrong

 It is just as

important to know what faults are not present as well as faults that do need to be addressed

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DG Screws

 STIHL uses the DG type of

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fastener in manufacturing because they cut their own threads the first time they are used

 Notice that the ones holding into

plastic have a different pitch and profile than the ones that hold into

For Plastic

For Metal

metal

 It is imperative that the Service Technician keep track of which

screw is which and not screw them into the wrong base material or the threads will be damaged

 It is also best practice that when starting a DG screw into the

hole, slowly rotate it backwards until it “clicks” to index the threads, then turn it clockwise to tighten it

1. Deflectors, Shrouds, Covers, Fasteners

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 Visually look the unit over for damage, missing items, loose

fasteners, or anything else that is obvious

Damaged shroud may be a

safety hazard for the operator

Operated without

an air filter or cover

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2. Warning Labels

 Verify that warning labels

are present and readable

 On a chain saw the only

label the service technician should be concerned with is the one on the chain brake handle

 If this label is damaged or

worn away, a universal

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replacement label is available from STIHL

 White Chain Saw Label:

0000 967 3613

3. Cutting Attachment

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 Note type and condition  Inspect for wear or damage

 Bar, chain, and sprocket

within wear limits

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3. Cutting Attachment 4. Belt Tension

 If the unit is a trimmer or a concrete saw:

 Tap head eyelets worn, spool worn, retainer secure  Belt tension correct; belt worn or frayed

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5. Operator Controls

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 The interlock should

be sticking up out of the handle, and it must be depressed flush with the handle before the throttle trigger will move

 Be sure the throttle

moves freely

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5. Operator Controls

 The throttle must be squeezed all the way open before the

Master Control Lever™ can be actuated to the full choke position, then release the throttle and the Master Control Lever™ should stay in the choke position

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5. Operator Controls

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 Now raise the Master

Control Lever™ up one notch with your thumb, and it should stay in the warm start, half choke position

 Now squeeze the trigger

and it should snap up to the I position automatically

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5. Operator Controls

 Finally the Master

Control Lever™ should easily slide up to the O position

 Any problem with the

Master Control

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Lever™ should be noted for repair

5. Operator Controls

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 When the chain

brake handle is actuated back and forth, there should be an audible “click”

 In the forward

position the sprocket must not turn

 In the back

position the sprocket must spin easily

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6. Verify Anti-vibration Components

 Most STIHL chain saws and line

trimmers have an anti-vibration system that should be inspected for wear and damage

 Some models do not have any anti-

vibration components so this step would not apply

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6. Verify Anti-vibration Components

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 Hold the bumper spike

against the edge of the workbench and put pressure against the handle assemble

 There should be strong

resistance to movement but there should be some “give” to the antivibe rubber bushings

 There should not be any

looseness to the handle assembly

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7. Inspect Starter System

 Inspect rope, handle, and eyelet for wear or damage  Pull the rope to it’s full extended length and be sure it is

not about to break at the very end

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8. Inspect Air Filter 9. Inspect Air Filter Housing

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 Remove cover and the top

of the filter is the clean side

 There should not be dirt or

debris on this side of the filter or down in the throat of the air intake

 Remove the filter and the

bottom side is the dirty side

 There should be a pinch

mark all the way around the edge of the filter to seal it

 Verify that the housing is not

cracked or damaged

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10. Carburetor Mixture Screws

 Most STIHL products have

mixture adjustment screws on the carburetor and will be equipped with a limiter cap on the H mixture screw and may have one on the L screw also

 The limiter cap allows the

operator to adjust the carb leaner only to compensate for operation in high altitude

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 If a cap is missing it should

be considered as a fault and it is possible the screw may be set too lean

L mixture screw with

cone to guide the

screwdriver in place

H mixture screw

with limiter cap in

the up, or released

position to allow the

technician to make

adjustments

10. Carburetor Mixture Screws

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 The 1130 saws do not have

mixture screws or limiter caps

 Notice that the H and L holes are

not threaded and are blocked off internally

 The only adjustment on a 1130

saw is to set the idle speed with this screw

 It also makes slight mixture

adjustments as the idle speed is tuned

 This carburetor uses a fixed

orifice jet to regulate the amount of fuel available to the engine

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and is not adjustable

10. Carburetor Screw Settings

 Limiter caps can be removed by

the service technician for carb service

 Removal of this style of limiter

cap is done with the 5910 890 4501 tool

 Anytime a cap is removed best

practice is to replace it with a new one

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 4229 121 2701

 On the 1130 saws this step

does not apply

Hose Removal

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 The 5910 890 4501 tool also works well to remove fuel,

impulse, or vent hoses

 Use a side to side rocking

motion while pushing against the hose to walk it off of the fitting

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11. Spark Plug Connection

 Use a twisting motion to remove the spark plug connection

and be careful not to pull the clip out of the high tension lead

 Inspect it for damage, hardness or cracks

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12. Spark Test

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 Connect a spark

tester and pull the rope through as if trying to start the engine

 If no spark is present

try again with a new plug

 A fouled or

defective spark plug may not show spark on the tester even if the ignition system is OK

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12. Spark Test

 If there is still a no

spark condition with a new plug, carefully disconnect the ground wire from the terminal on the ignition module and now see if spark is present

 If there is no spark the

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module is faulty

 If there is spark the

stop circuit is faulty

12. Ignition Shut-Off Function

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 If spark is present then place the Master Control Lever™ in

the off position and pull the rope through and verify that no spark is present

 This verifies that the stop switch and connecting wiring is in

order

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13. Spark Plug

 Verify that the correct plug is installed for an 1130 saw:

 Bosch WSR6F STIHL Part Number 1110 400 7005  NGK BPMR7A STIHL Part Number 0000 400 7000

 Other units may use a different part number with a different

heat range, so always look it up!

 Set all STIHL spark plugs at .020”

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13. Spark Plug Appearance

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Normal color,

normal electrode wear due to high run time

Normal color and

wear

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Heavy

carbon buildup and oil fouled

Mix ratio

incorrect.

Carbon buildup

due to high run time

Both of these

plugs have served their useful life

14. Muffler

 Remove the 2 muffler nuts and

Black, sooty

appearance

Caused by

rich fuel/air mixture

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deflector plate and inspect the spark arrester screen

 It must be present for all hand

held engines used in the United States

 The screen may be blocked

with carbon deposits

 If necessary shine a light

through the screen to verify

Remove Starter Housing

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 Remove fuel and oil tank caps  Rock the cap retainer to the side  Remove starter housing

 Reinstall the caps if necessary to prevent fuel or oil from

running out on the work area

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15. Cylinder Leak Down Test

 This test typically is not

necessary on a two-stroke engine but can be done to verify how well the rings are sealing with the flywheel blocked so the piston is slightly down from TDC

 A leak down test should always

be done on a four-stroke engine because the piston and rings cannot be observed visually

 The leak down test also verifies

that the intake and exhaust valves are sealing properly

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16. Inspect Exhaust Port and Piston

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 With the muffler removed use

a flashlight and look through the exhaust port to be sure the port is not clogged up with carbon deposits

 Move the piston up and down

and inspect the surface of the piston skirt for scoring or damage

 A piston in good condition

will still have the radial machine marks across the skirt indicating little or no wear

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16. Inspect Exhaust Port and Piston

 Spray some lubricant on

the rings and when the flywheel is turned back and forth slightly it will be apparent if the rings are free in the lands

 Lower the piston to BDC

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 Inspect the intake side of

the cylinder wall for wear or damage

17. Cooling System

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 Verify that the cooling fins are in good condition and that the

air path to the flywheel and through the engine from the flywheel is not blocked or restricted in any way

 Verify that the flywheel fins are in good condition

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18. Magneto Air Gap

 Line up the pole shoes in the

flywheel with the magneto

 Observe the gap between the

ignition module and the flywheel

 The specification is .008”  It is not absolutely

necessary to measure this with a gauge, just be sure

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the flywheel is not rubbing on the module and that the gap does not look excessively wide

19. Fuel Tank

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 If the tank is empty look down in the tank to see if it appears

contaminated with debris or anything else that shouldn’t be there

 If the unit has fuel in it carefully remove the cap and wave your

hand over the opening while smelling for a sour odor that may indicate old stale fuel

19. Fuel Tank

 If fuel is present carefully pour the fuel out in a pan and see if

there is trash or debris, or any evidence of other contaminants such as water in the fuel

 This sample is

contaminated with water and debris

 Dispose of fuel properly

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20. Fuel Filter

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 Use the 5910 893 880 hook tool to fish the fuel filter out of the

tank for inspection

 The filter body screen should be clear and in good condition,

and the element may have oil staining but should not be dark or fouled or have any kind of coating on it

Pressure Vacuum Tester

 0000 850 1300 Pump  With the knurled ring to

the right the gauge indicates pressure

 With the knurled ring to

the left the gauge

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indicates vacuum

20. Fuel Filter

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 It is a good idea to backflow a fuel filter with the pressure

pump to verify that it is not restricted

 Hook up the tester and place the filter on a towel and pump

the tester 2 times

 No pressure should build up and if the filter is wet with fuel

it should clearly flow out

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21. Pressure Test Fuel Line

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 Connect the pressure tester to the fuel line where the filter was

removed and gently pump it up no higher than 10 PSI

 If it holds steady then the fuel line is OK, and the carb itself

passes the pressure test

 If the gauge does not

hold then either the fuel line or the carb may be leaking, so isolate the fuel line and test it by itself to determine where the fault is

Remove Carb

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 Hold the choke shutter closed and carefully remove the link

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Remove Carb

 Carefully slide the fuel line off of the fitting

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Remove Carb

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 Hold the throttle wide open and carefully remove the link

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Remove Carb

 Gently pry the Master Control Lever™ up on the left side

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Remove Carb

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 Slide the Master Control Lever™ to the left and let it hang

out of the way by the ground wire

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Remove Carb

 Hold the fuel line down out of the way and slide the carb off

of the studs

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21. Pressure Test Fuel Line

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 To test the fuel line by itself, plug one end and test through the

other

 It should hold steady at 10 PSI

22. Pressure Test Tank

 Be sure there is no fuel

in the tank before applying any pressure to the fuel tank!

 The pressure test

verifies that the tank does not have a leak in any location, such as a grommet, seam, cap or

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hose

 Apply about 8 PSI max and it must hold steady  If it leaks down at all use soapy water in a spray bottle

to locate where the leak is

23. Vacuum Test Tank Vent

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 Reverse the tester into

vacuum mode and pump hard and fast to see the needle indicates that some negative pressure is present in the tank

 Stop pumping and watch

the gauge and the needle should move back up towards zero rapidly

 If the needle does not

leak back to zero quickly the tank vent must be replaced and then re-test

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24. Inspect Intake Side Of Piston

 With the carb removed

look through the inlet port and rotate the crankshaft to inspect the intake side of the piston

 The machine marks

should be present on a piston in good condition

 Scoring or a dull gray

appearance would indicate lack of lubrication, dirt ingestion, or possibly other problems that would prevent the engine from running properly

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25. Impulse Signal Present

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 Most two-stroke engines have a

passageway between the crankcase and the fuel pump side of the carburetor to cause the fuel pump diaphragm to flex back and forth with the pressure/vacuum that is created by the piston moving up and down

 It is rare that there is no impulse

signal, but always verify that it is present because no impulse signal will cause a hard to diagnose, unusual running behavior that will appear to be carburetor related

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For this blower engine the

impulse signal comes out

through the flange here:

25. Impulse Signal Present

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 For the 1130 saw, remove the white plastic sealing ring, use

the tapered adapter and connect the tester to the impulse port

 By hand, rotate the flywheel back and forth and the needle on

the gauge should bounce back and forth indicating the impulse signal is present

26. Vacuum and Pressure Test of Crankcase

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 A two-stroke engine needs an air tight crankcase since the air

fuel mix is coming through the crankcase on the way to the combustion chamber

 Test to verify that there are no leaks at places like gaskets or

RTV silicone sealed mating surfaces, and that crankshaft seals are not leaking under pressure or vacuum

 Block off the exhaust port

by slipping a rubber block off plate in between the cylinder and the adapter plate, then install spacers and snug up the nuts while pulling the rubber up to get a complete seal

26. Vacuum and Pressure Test of Crankcase

 The Service Manual for each

model describes how to do this test and gives the part number for the adapters

 For the 1130 saw the special

adapter for the carb side is part number 1118 850 4200

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 Be sure the spark plug is

installed and tight

26. Vacuum and Pressure Test of Crankcase

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 Use the tester to pull a 0.5 bar vacuum; it should hold steady

or not leak back to 0.3 bar within 20 seconds

 Rotate the crankshaft back and forth while the crankcase is

under vacuum to verify that the seals are holding properly

 Pump 0.5 bar of pressure into the engine and it should hold

steady for at least 20 seconds

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Pressure Test Results

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 If the unit fails the pressure test check obvious things first, such

as the rubber sealing plate on the exhaust and the spark plug, by spraying with soapy water and looking for bubbles

 If they are sealing properly then the engine may need to be

taken apart far enough to be able to check the crankshaft seals and the seal between the cylinder and the crankcase

 If an engine leaks under vacuum but holds under pressure it is

most likely a crankshaft seal

27. Crankshaft and Bearing Condition

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 See if the flywheel moves in and out or up and down  There should not be any loose play in the crankshaft

bearings

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28. Carburetor

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 Pressure test the carb no higher than 10 PSI and it should hold

steady

 Open and close the butterfly and it should open smoothly  Verify that the throttle shaft does not have any excessive side

to side play

 Inspect the carb for any physical damage

29. Other Observations; Final Running

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 This is where any other observations about the unit not

specifically covered by one of the numbered items on the STIHL Engine Check can be recorded

 Once repairs have

been made the last part of the STIHL Engine Check document can be used as a quality control check to be sure the engine starts easily and is running to specification

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Final Check: Roll Out Test

 With the engine warmed

up and idling, and the chain brake engaged on a saw, slowly roll the engine over so one side faces the ground

 Now roll it back upright,

then roll the other side towards the ground

 Idle RPM should not

change more than 200300 RPM

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 If the idle changes the

engine may have an air leak or other fault

This presentation has been prepared by:

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Eddie Anderson Technical Training Supervisor STIHL Inc. Virginia Beach, VA eddie.anderson@stihl.us

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Stihl MS 18, MS 170 Servise Manual

Specifications and Main Features

Frequently Asked Questions

User Manual