Cessna 172N Operating Handbook page 51

CESSNA
MODEL 172N
SECTION 4
NORMAL PROCEDURES
A MP T IF IE D PR OCEDU RES
ST AR, TIN G E NGINE
During ergine starting, open the throttle approximately f/g inch. In
warm temperatures,
one or hvo strokes of the primer should be zufficient.
In cold weather, up to six strokes of the primer may be necessary. If the
engine is warm, no primirg will be required.
In extremely cold temper-
atures, it may be necessary to continue priming while cranking the engine.
Weak intermittent firing followed by puffs of black smoke from the
exhaust stack indicate overpriming or flooding. Excess fuel can be
cleared from the combiustion chambers by the following procedure: Set
the mixfure control full lean and the throttle full open; then crank the en-
gine through several revolutions with the starter.
Repeat the starting
procedure without any additional priming.
If the engine is underprimed (most likely in cold weather with a cold
engine) i+'will not fire at all, and additional priming will be necessary.
As soon as the cylinders begin to fire, open the throttle slightly to keep it
running.
After starting, if the oil gage does not begin to show pressure within
30 seconds in the zummertime and about twice that long in very cold
weather, stop engine and investigate,
I-ack of oil pressure can cause
seriors ergine damage. After starting, avoid the use of carbretor heat
unless icing conditions prevail.
NOTE
Additional details concerning cold weather starting and
operation may be found under COLD WEATHER OPERA-
TION paragraphs in this section.
TAX IIN G
When taxiing, it is important that speed and use of brakes be held to
a minimum and that all controls be utilized (see Taxiing Diagram, figure
4-2\ to maintain directional control and balance.
The carburetor heat control lcrob should be pushed full in during all
ground operations unless heat is absolutely necessary.
When the lmob is
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