Headlight, Throttle control, Clean-out tool – MTD 643 User Manual
Page 7: Before starting, Gas and oil fill-up

7
Headlight
The headlight is on whenever the engine is running.
Throttle Control
The throttle control is located on the engine. It regulates 
the speed of the engine and will shut off the engine 
when pushed down completely. See Figure 5.
Clean-Out Tool
The chute clean-out tool is fastened to the top of the 
auger housing with a mounting clip. The tool is 
designed to clear a clogged discharged chute. Refer to
Operating Your Snow Thrower
section for more detailed
information regarding the chute clean-out tool.
See Figure 5.
WARNING: Never use your hand to clear a
clogged discharged chute. Shut off
engine and remain behind handles until
all moving parts have stopped before
unclogging.
SECTION 4: OPERATING YOUR SNOW THROWER
Before Starting
WARNING: Read, understand, and follow
all instructions and warnings on the
machine and in this manual before
operating.
Gas And Oil Fill-up
Service the engine with gasoline and oil as 
instructed in the separate engine manual packed with 
your snow thrower. Read instructions carefully.
WARNING: Use extreme care when
handling gasoline. Gasoline is extremely
flammable and the vapors are explosive.
Never fuel machine indoors or while the
engine is hot or running. Extinguish
cigarettes, cigars, pipes an other sources
of ignition.
•
A plastic cup is provided inside the fuel fill opening 
on the fuel tank. Remove and discard this cup 
before filling up the tank. Use the separate fuel tank 
cap to close after fill-up.
To Start Engine
•
Attach spark plug wire to spark plug. Make certain 
the metal loop on end of the spark plug wire (inside 
the boot) is fastened securely over the metal tip on 
the spark plug.
•
Make certain the fuel cut-off valve, if your snow 
thrower is so equipped, is in OPEN position.
•
Make certain the auger and drive clutch levers are 
in the disengaged (released) position.
•
Move throttle control up to FAST position. Insert 
ignition key into slot. Be certain it snaps into place. 
Do not turn key. 
NOTE: Engine will not start unless ignition key is
inserted into ignition slot in carburetor cover. 
Electric Starter
•
Determine that your house wiring is a three-wire 
grounded system. Ask a licensed electrician if you 
are not certain.
•
If your house wiring system is not a three-wire 
grounded system, do not use this electric starter 
under any conditions.
WARNING: The electric starter is
equipped with a grounded three-wire
power cord and plug and is designed to
operate on 120 volt AC household
current. It must be used with a properly
grounded three-prong receptacle at all
times to avoid the possibility of electric
shock. Follow all instructions carefully
prior to operating the electric starter.
•
If your home electrical system is grounded, but a 
three-hole receptacle is not available, one should 
be installed by a licensed electrician before using 
the electric starter.
•
If you have a grounded three-prong receptacle, 
proceed as follows:
•
Rotate choke knob to OFF position and do not 
prime engine.
•
Connect power cord to switch box on engine. Plug 
the other end of power cord into a three-hole, 
grounded 120 volt AC receptacle.
•
Push starter button on top of the engine to crank 
engine. As you crank the engine, move choke knob 
to FULL choke position.
•
When engine starts, release starter button, and 
move choke gradually to OFF. If engine falters, 
move choke immediately to FULL and then 
gradually to OFF.
•
When disconnecting the power cord, always unplug 
from the three-prong receptacle first and then from 
the snow thrower.
