Cessna 1973 172 - Cold Weather Operation; Starting

COLD WEATHER OPERATION. /->
STARTING. ^
Prior to starting on a cold morning, it is advisable to pull the pro-
peller through several times by hand to "break loose" or "limber" the
oil, thus conserving battery energy.
NOTE
When pulling the propeller through by hand, treat it as if
the ignition switch is turned on. A loose or broken ground
wire on either magneto could cause the engine to fire.
In extremely cold (0°F and lower) weather, the use of an external pre-
heater and an external power source are recommended whenever possible
to obtain positive starting and to reduce wear and abuse to the engine and
electrical system. Pre-heat will thaw the oil trapped in the oil cooler,
which probably will be congealed prior to starting in extremely cold tem-
peratures. When using an external power source, the position of the
master switch is important. Refer to Section VII xmder Ground Service
Plug Receptacle for operating details.
Cold weather starting procedures are as follows:
With Preheat:
(1) With ignition switch OFF and throttle closed, prime
the engine four to eight strokes as the propeller is being
turned over by hand.
NOTE
Use heavy strokes of primer for best atomization of fuel.
After priming, push primer all the way in and turn to
locked position to avoid possibility of engine drawing fuel
through the primer.
(2) Propeller Area ~ Clear. _
(3) Master Switch — ON.
(4) Mixture — Full rich.
(5) Throttle — Open 1/8".
. (6) Ignition Switch — START.
(7) Release ignition switch to BOTH when engine starts.
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