MTD ZS 161-SH User manual

Safety • Operation • Maintenance • Storage • Troubleshooting
MTD PRODUCTS AKTIENGESELLSCHAFT • SAARBRÜKEN • GERMANY
READ SAFETY RULES AND INSTRUCTIONS CAREFULLY BEFORE OPERATION
IMPORTANT
OPERATOR’S MANUAL
Engine — Model ZS 161-SH
08/18/2006
FORM NO. 769-02627

2
Table of Contents
This manual covers the operation and maintenance of your
engine:
All information in this publication is based on the latest product
information available at the time of printing.
No part of this publication may be reproduced without written
permission.
This manual should be considered a permanent part of the
engine and should remain with it if it is resold.
Pay special attention to statements preceded by the following
words:
WARNING: Indicates a strong possibility of
severe personal injury or death if instructions
are not followed.
This Operator’s Manual is an important part of your new engine. It will help you
prepare and maintain the unit for best performance. Please read and understand what it says.
Safe Operation Practices................................... 4
Operating Your Engine ....................................... 6
Maintaining Your Engine .................................... 8
Troubleshooting................................................ 11
IMPORTANT: Indicates a possibility of equipment or property
damage if instructions are not followed.
NOTE: Gives helpful information.
If a problem should arise, or if you have any ques-
tions about your engine, consult the dealer.
IMPORTANT: The engine is designed to give safe
and dependable service if operated according to
instructions. Read and understand the Operator’s
Manual before operating the engine. Failure to do so
could result in personal injury or equipment damage.

3
NOTES
Use this page to make notes and write down important information.

4
1
Engine
Safe
Operation
Practices
• When adding fuel, turn engine OFF and let engine
cool at least 2 minutes before removing gas cap.
• Fill fuel tank outdoors or in well ventilated area.
• Use only an approved gasoline container.
• Never fill containers inside a vehicle or on a truck or
trailer bed with a plastic liner. Always place contain-
ers on the ground away from your vehicle before
filling.
• If possible, remove gas-powered equipment from the
truck or trailer and refuel it on the ground. If this is
not possible, then refuel such equipment on a trailer
with a portable container, rather than from a gasoline
dispenser nozzle.
• Keep the nozzle in contact with the rim of the fuel
tank or container opening at all times until fueling is
complete. Do not use a nozzle lock-open device.
• Do not overfill fuel tank. Fill tank to approximately
2 cm below lowest portion of neck to allow for fuel
expansion.
• Keep gasoline away from sparks, open flames, pilot
lights, heat, and other ignition sources.
• Never fuel equipment indoors because flammable
vapors will accumulate in the area.
• Extinguish all cigarettes, cigars, pipes, and other
sources of ignition.
• Check fuel line, tank, cap, and fittings frequently for
cracks or leaks. Replace if necessary.
• When starting engine, make sure spark plug, muffler,
fuel cap and air cleaner are in place.
• Do not crank engine with spark plug removed.
• If fuel spills, wait until it evaporates before starting
engine.
• When operating equipment, do not tip engine or
equipment at angle which causes gasoline to spill.
• Do not choke carburetor to stop engine.
• When transporting equipment, transport with fuel
tank EMPTY.
• When storing gasoline or equipment with fuel in tank,
store away from furnaces, stoves, water heaters or
other appliances that have pilot light or other ignition
source because they can ignite gasoline vapors.
Starting engine creates spark-
ing. Sparking can ignite nearby
flammable gases. Explosion and
fire could result.
• If there is a natural or LP gas leakage in area, do not
start engine.
• Do not use pressurized starting fluids because vapors
are flammable.
Engines give off carbon mon-
oxide, an odorless, colorless,
poisonous gas. Breathing carbon
monoxide can cause nausea,
fainting, or death.
• Start and run engine outdoors.
• Do not start or run engine in enclosed area, even if
doors or windows are open.
Unintentional sparking can result
in fire or electric shock. Unin-
tentional start-up can result in
entanglement, traumatic amputa-
tion, or laceration.
• Before performing adjustments or repairs, disconnect
spark plug wire and keep it away from spark plug.
• When testing for spark, use approved spark plug
tester.
• Do not check for spark with spark plug removed.
WARNING: Gasoline and its vapors are extremely flammable and explosive. Fire or
explosion can cause severe burns or death. If gasoline is spilled on yourself or your
clothes, wash your skin and change clothes immediately.
WARNING
Gasoline and its vapors
are extremely flammable
and explosive. Fire or ex-
plosion can cause severe
burns or death. If gasoline
is spilled on yourself or
your clothes, wash your
skin and change clothes
immediately.
Starting engine creates
sparking. Sparking can
ignite nearby flammable
gases. Explosion and fire
could result.
Unintentional sparking
can result in fire or elec-
tric shock. Unintentional
start-up can result in
entanglement, traumatic
amputation, or laceration.

5
Running engine produces heat.
Engine parts, especially muffler,
become extremely hot. Severe
thermal burns can occur on
contact. Combustible debris,
such as leaves, grass, brush, etc.,
can catch fire.
• Allow muffler, engine cylinder, and fins to cool before
touching.
• Keep children away from hot or running engines. They
can suffer burns from a hot muffler.
• Remove accumulated combustibles from muffler and
cylinder area.
Rotating engine parts can
contact or entangle hands, feet,
hair, clothing, or accessories.
Traumatic amputation or severe
laceration can result.
• Operate equipment with guards in place.
• Keep hands and feet away from rotating parts.
• Tie up long hair and remove jewelry.
• Do not wear loose-fitting clothing, dangling draw-
strings or items that could become caught.
Rapid retraction of starter cord
(kickback) will pull hand and
arm toward engine faster than
you can let go. Broken bones,
fractures, bruises or sprains
could result.
• When starting engine, pull cord slowly until resis-
tance is felt, then pull rapidly.
• Remove all external equipment/engine loads before
starting engine.
• Direct coupled equipment components such as, but
not limited to blades, impellers, pulleys, sprockets,
etc., must be securely attached.
Safety Label Location
This label warns you of potential hazards that can
cause serious injury. Read it carefully. Refer to Figure
1-1 for explanation of symbols. If the label comes off or
becomes hard to read, contact the dealer for replace-
ment.
1
Engine
Safe
Operation
Practices
WARNING
Running engine produces
heat. Engine parts, es-
pecially muffler, become
extremely hot. Severe
thermal burns can occur
on contact. Combustible
debris, such as leaves,
grass, brush, etc., can
catch fire.
Rotating engine parts
can contact or entangle
hands, feet, hair, clothing,
or accessories. Traumatic
amputation or severe
laceration can result.
Rapid retraction of starter
cord (kickback) will pull
hand and arm toward
engine faster than you
can let go. Broken bones,
fractures, bruises or
sprains could result.
P B
2UN
3TART
4OXIC&UMES
(OT3URFACE
3AFETY!LERT
5NLEADED&UEL
-ANUAL
2EAD/WNERS
'ASOLINE)S
&LAMMABLE
0 "
International Symbols and Meanings
Figure 1-1: International symbols and meanings.

6
Choke Control
Activating choke control by sliding it all the way to the
right closes the choke plate on carburetor and aids in
starting engine. For information on choke usage, see
“Starting The Engine”. The image above corresponds
with the label on the engine identifying the Choke
control.
Recoil Starter & Starter Handle
This motor is fitted with a recoil action pull start and a
mitten grip handle for easy access while wearing gloves
or mittens.
Ignition Key
The ignition key is necessary for the
engine to start. Insert key and snap in
place; do not turn it to start/stop the
unit. Pull the key out halfway to stop
the engine.Remove key when the unit
is not in use.
Primer
Depressing primer forces fuel directly into engine’s
carburetor to aid in cold-weather starting. Refer to the
starting instructions in the Operation section of this
manual for proper primer usage. The image above,
corresponds with the label on the engine identifying the
priming steps.
2
Operating
Your
Engine
Know Your Engine
Oil Fill
Remove oil cap to add oil. Refer to “Pre-Operation
Check” section for checking oil and “Maintaining Your
Engine” section for adding oil instructions.
Gasoline Cap
Remove gas cap to add fuel. Unit runs on automotive
unleaded gas.
Pre-Operation Check
Oil Recommendations
IMPORTANT: This engine is shipped without gasoline or
oil in the engine. Running the engine with insufficient oil
can cause serious engine damage and void the engine
warranty.
• Before starting engine, fill with 5W-30 oil. Engine oil
capacity is 600 ml. Do not over-fill.
Use a 4-stroke, or an equivalent high detergent, premium
quality motor oil certified to meet or exceed U.S. automo-
bile manufacturer’s requirements for service classification
SG, SF. Motor oils classified SG, SF will show this
designation on the container.
IMPORTANT: DO NOT use nondetergent oil or 2-stroke
engine oil. It could shorten the engine’s service life.
Check Oil Level
IMPORTANT: Be sure to check the engine on a level
surface with the engine stopped.
1. Remove the oil filler cap and wipe the dipstick clean,
Figure 2-2.
Read this section before starting your engine. Compare the illustrations in Figure 2-1 with your engine to familiarize
yourself with the location of various controls and adjustments.
IMPORTANT: This engine
is shipped without gaso-
line or oil in the engine.
Running the engine with
insufficient oil can cause
serious engine damage
and void the engine
warranty.
IMPORTANT: DO NOT
use nondetergent oil or 2-
stroke engine oil. It could
shorten the engine’s
service life.
Be sure to check the
engine on a level surface
with the engine stopped.
Figure 2-1: The major components of the engine.
On
Off
PRIMER
Choke Control
Starter Handle
Oil Fill
Spark Plug
Oil Drain
Muffler

7
NOTE: Always cover vent hole in primer button when
pushing. Additional priming may be necessary for first
start if temperature is below -10 degrees Celsius.
5. Grasp starter handle and pull rope out slowly, until it
pulls slightly harder. Let rope rewind slowly.
6. Pull starter handle rapidly. Do not allow handle to
snap back. Allow it to rewind slowly while keeping a
firm hold on the starter handle.
7. As engine warms up and begins to operate evenly,
rotate choke lever slowly to the 1/2 Choke position.
When the engine begins to run smoothly, move the
choke to the OFF position. If engine falters, return
to FULL choke, then slowly move to 1/2 then OFF
position.
Stopping The Engine
1. To stop engine, pull ignition key out halfway.
Disconnect the spark plug wire from the spark plug
to prevent accidental starting while equipment is
unattended.
2. Insert the dipstick into the oil filler neck, but do not
screw it in.
3. If the level is low, slowly add oil to the upper limit on
the dipstick. See Figure 2-2 inset.
4. Tighten dipstick firmly before starting engine.
IMPORTANT: Do not overfill. Overfilling with oil may
cause smoking, hard starting, spark plug fouling, or oil
saturation of air cleaner.
Fuel Recommendations
Use automotive gasoline (Unleaded or lowleaded to
minimize combustion chamber deposits). Never use an
oil/gasoline mixture or dirty gasoline. Avoid getting dirt,
dust, or water in the fuel tank.
WARNING: Gasoline is extremely flam-
mable and is explosive under certain
conditions.
Refuel in a well-ventilated area with the engine stopped.
Do not smoke or allow flames or sparks in the area
where the engine is refueled or where gasoline is stored.
Do not overfill the fuel tank (there should be no fuel in
the filler neck). After refueling, make sure the tank cap is
closed properly and securely.
Be careful not to spill fuel when refueling. Spilled fuel or
fuel vapor may ignite. If any fuel is spilled, make sure the
area is dry before starting the engine.
Avoid repeated or prolonged contact with skin or breath-
ing of vapor.
Check Fuel Level
1. Clean around fuel fill before removing cap to fuel.
2. Fill tank to approximately one inch below lowest
portion of neck to allow for fuel expansion. Be careful
not to overfill.
IMPORTANT: Before refueling, allow engine to cool two
minutes.
Starting The Engine
WARNING: Always keep hands and
feet clear of equipment moving parts.
Do not use a pressurized starting fluid.
Vapors are flammable.
1. Insert ignition key fully into slot. See Figure 2-3.
2. Move choke lever to the ON position (cold engine
start).
3. If engine is warm, place choke in OFF position
instead of ON.
4. Push primer five to seven (5-7) times, making sure
to cover vent hole when pushing. See Figure 2-3. If
engine is warm, push primer button only once.
2
Operating
Your
Engine
WARNING
Gasoline is extremely
flammable and is explosive
under certain conditions.
IMPORTANT: Do not
allow the starter grip to
snap back against the
engine. Return it gently
to prevent damage to the
starter.
Figure 2-2: Checking the oil level.
Figure 2-3: Primer and ignition key location.
Always keep hands and
feet clear of equipment
moving parts. Do not use a
pressurized starting fluid.
Vapors are flammable.
Upper Level
Ignition Key
Primer

8
Tasks First 5
Hrs.
Each Use or
Every 5 Hrs.
Every Season
or 25 Hrs.
Every Season
or 50 Hrs.
Every Season
or 100 Hrs.
Service Dates
Check Engine Oil
Change Engine
Oil
Check Spark Plug
Service Spark
Plug
Clean Around
Muffler
Oil Service
• Check oil level regularly.
• Be sure correct oil level is maintained. Check every five
hours or daily before starting engine. See oil checking
procedure in the Operation section.
Oil Change
IMPORTANT: Be sure to check engine on a level surface
with the engine stopped. Drain the oil while the engine is
still warm to assure rapid and complete draining.
1. Remove oil fill cap and drain oil by removing drain
plug and allowing oil to drain into a suitable container,
Figure 3-1.
3
Maintaining
Your
Engine
WARNING
Shut off the engine before
performing any type of
maintenance. To prevent
accidental start-up,
disconnect the spark plug
boot.
WARNING: Shut off the engine before
performing any maintenance. To
prevent accidental start-up, disconnect
the spark plug boot.
IMPORTANT: If engine must be tipped to transport
equipment or to inspect, keep spark plug side of engine
up. Transporting or tipping engine spark plug down may
cause smoking, hard starting, spark plug fouling, or oil
saturation of air cleaner.
Periodic inspection and adjustment of the engine is
essential if high level performance is to be maintained.
Regular maintenance will also ensure a long service life.
The required service intervals and the kind of mainte-
nance to be performed are described in the table below.
Follow the hourly or calendar intervals, whichever occur
first. More frequent service is required when operating in
adverse conditions.
Maintenance Schedule
Before tipping engine or
equipment to drain oil,
drain fuel from tank by
running engine until fuel
tank is empty.
IMPORTANT: Be sure to
check engine on a level
surface with the engine
stopped. Drain the oil
while the engine is still
warm to assure rapid and
complete draining.
Figure 3-1: Changing the oil.
Oil Fill
Oil Drain
Plug
Level

9
4. Check that the spark plug washer is in good condition
and thread the spark plug in by hand to prevent
cross-threading.
5. After the spark plug is seated, tighten with a spark
plug wrench to compress the washer.
NOTE: When installing a new spark plug, tighten 1/2 turn
after the spark plug seats to compress the washer. When
reinstalling a used spark plug, tighten 1/8-1/4 turn after
the spark plug seats to compress the washer.
IMPORTANT: The spark plug must be securely tight-
ened. An improperly tightened spark plug can become
very hot and may damage the engine.
WARNING: Before tipping engine or
equipment to drain oil, drain fuel from
tank by running engine until fuel tank
is empty.
2. Reinstall the drain plug (if removed), and tighten it
securely.
3. Refill with the recommended oil (see Operation
section) and check the oil level, Figure 3-1.
4. Reinstall the oil fill cap securely.
IMPORTANT: Used motor oil may cause skin cancer
if repeatedly left in contact with the skin for prolonged
periods. Although this is unlikely unless you handle used
oil on a daily basis, it is still advisable to thoroughly wash
your hands with soap and water as soon as possible
after handling used oil.
NOTE: Please dispose of used motor oil in a manner that
is compatible with the environment. We suggest you take
it in a sealed container to your local service station for
reclamation. Do not throw it in the trash or pour it on the
ground.
Spark Plug Service
WARNING: DO NOT check for spark
with spark plug removed. DO NOT
crank engine with spark plug removed.
To ensure proper engine operation, the spark plug must
be properly gapped and free of deposits.
1. Remove the spark plug boot and use a spark plug
wrench to remove the plug, Figure 3-2.
WARNING: If the engine has been
running, the muffler will be very hot. Be
careful not to touch the muffler.
2. Visually inspect the spark plug. Discard the spark
plug if there is apparent wear, or if the insulator is
cracked or chipped. Clean the spark plug with a wire
brush if it is to be reused.
3. Measure the plug gap with a feeler gauge. Correct as
necessary by bending side electrode, Figure 3-3. The
gap should be set to 0.60-0.80mm.
3
Maintaining
Your
Engine
WARNING
Never use gasoline or low
flash point solvents for
cleaning the air cleaner
element. A fire or explo-
sion could result.
DO NOT check for spark
with spark plug removed.
DO NOT crank engine
with spark plug removed.
If the engine has been
running, the muffler will
be very hot. Be careful
not to touch the muffler.
Figure 3-2: The spark plug and boot.
Figure 3-3: Measure the plug gap with a feeler gauge.
Spark Plug
Spark Plug Boot
Electrode
0.60-0.80mm

10
Clean Engine
If the engine has been running, allow it to cool for at
least half an hour before cleaning. Periodically remove
dirt build-up from engine. Clean finger guard and around
muffler. Clean with a brush or compressed air.
IMPORTANT: Do not spray engine with water to clean
because water could contaminate fuel. Using a garden
hose or pressure washing equipment can also force wa-
ter into the muffler opening. Water that passes through
the muffler can enter the cylinder, causing damage.
WARNING: Accumulation of debris
around muffler could cause a fire.
Inspect and clean before every use.
Storage
Engines stored over 30 days need to be drained of fuel
to prevent deterioration and gum from forming in fuel
system or on essential carburetor parts. If the gasoline
in your engine deteriorates during storage, you may
need to have the carburetor, and other fuel system
components, serviced or replaced.
1. Remove all fuel from tank by running engine until it
stops from lack of fuel.
2. Change oil. See Oil Change section.
3. Remove spark plug and pour about 1/2 an ounce of
engine oil into cylinder. Replace spark plug and crank
slowly to distribute oil.
4. Clean debris from around engine, under finger guard,
and under, around and behind muffler. Touch up any
damaged paint, and coat other areas that may rust with
a light film of oil.
5. Store in a clean, dry and well ventilated area away from
any appliance that operates with a flame or pilot light,
such as a furnace, water heater, or clothes dryer. Also
avoid any area with a spark producing electric motor,
or where power tools are operated.
6. If possible, also avoid storage areas with high humidity,
because that promotes rust and corrosion.
7. Keep the engine level in storage. Tilting can cause fuel
or oil leakage.
Removing From Storage
1. Check your engine as described in the Pre-Operation
Check section of this manual.
2. If the fuel was drained during storage preparation, fill
the tank with fresh gasoline. If you keep a container
of gasoline for refueling, make certain it contains only
fresh fuel. Gasoline oxidizes and deteriorates over
time, causing hard starting.
3. If the cylinder was coated with oil during storage
preparation, the engine will smoke briefly at startup.
This is normal.
3
Maintaining
Your
Engine
WARNING
Accumulation of debris
around muffler could
cause a fire. Inspect and
clean before every use.
IMPORTANT: Do not
spray engine with water
to clean because water
could contaminate fuel.
Using a garden hose
or pressure washing
equipment can also force
water into the air cleaner
or muffler opening. Water
in the air cleaner will soak
the paper element, and
water that passes through
the element or muffler
can enter the cylinder,
causing damage.

11
For repairs beyond
the minor adjustments
listed here, contact
an authorized service
dealer.
4
Trouble
Shooting
Cause
Problem Remedy
Engine fails to start 1. Engine flooded from excessive priming.
2. Spark plug wire disconnected.
3. Fuel tank empty or stale fuel.
4. Engine not choked.
5. Faulty spark plug.
6. Blocked fuel line.
7. Engine not primed.
8. Key not in ON position.
1. Wait at least ten minutes before
starting.
2. Connect wire to spark plug.
3. Fill tank with clean, fresh gasoline.
4. Choke engine as instructed in the
“Operating Your Engine” section.
5. Clean, adjust gap, or replace.
6. Clean fuel line.
7. Prime engine 5-7 times.
8. Insert key fully to ON position.
Engine runs erratic 1. Connect and tighten spark plug wire.
2. Clean fuel line; fill tank with clean,
fresh gasoline.
3. Move choke lever to RUN..
4. Drain fuel tank. Refill with fresh fuel.
1. Spark plug wire loose.
2. Blocked fuel line or stale fuel.
3. Unit running with choke activated.
4. Water or dirt in fuel system.
Engine overheats 1. Fill crankcase with proper capacity and
weight of oil.
1. Engine oil level low.
Occasional skips
(hesitates) at high speed
1. Remove spark plug and reset gap as
instructed in the Maintenance section.
1. Spark plug gap too close.
Idles poorly 1. Replace spark plug and reset gap as
instructed in the Maintenance section.
1. Spark plug fouled, faulty or gap too wide.
NOTE: Specifications are
subject to change without
notification or obligation.
Images my not reflect your
exact model and are for
reference purposes only.

MTD PRODUCTS AKTIENGESELLSCHAFT • SAARBRÜKEN • GERMANY