Cessna 1971 Super Skymaster - Page 18

STARTING ENGINES.
Althuugh either engine may be started first and the procedure is
Idolllkill for both, the front engine is normally started first. The cable
fl'om thu oo.ttery to this engine is much shorter which permits more elec-
Ideal power to be delivered to the starter. If the battery is low, the
front ongine should
start more readily.
The continuous-flow fuel injection system will start spraying fuel in
the
intake ports as soon as the throttle and mixture controls are opened
and the auxiliary pump is turned on. If the auxiliary pump is turned on
aCCidentally while the engine is stopped, with the throttle open and the
mixture rich, solid fuel will collect temporarily in the cylinder intake
ports, the quantity depending on the amount of throttle opening and the
length of
time the pump has been operating. If this happens, it is ad-
visable to wait a few minutes until this fuel drains away before starting
the engine. To avoid flooding, be sure you are ready to crank the engine
as soon as a steady fuel flow of 10 to 25 lbs/hr is obtained.
Engine mis-starts characterized by weak, intermittent firing followed
by puffs of
black smoke from the exhaust are caused by overpriming or
flooding. This situation is more apt to develop in hot weather, or when
the engine
is hot. If it occurs, repeat the starting routine with the throttle
approximately 1/2 open, the mixture in idle cut-off and the auxiliary pump
off.
As the engine fires, move the mixture control to full rich and de-
crease the throttle to idle.
Engine mis-starts characterized by sufficient power to take the en-
gine away from the starter but dying in 3 to 5 revolutions are the result
of an excessively lean mixture after the start and can occur in warm or
cold temperatures. Repeat the starting procedure but allow additional
priming time with the auxiliary fuel pump switch in the "WW" position
before cranking is started, or place the auxiliary fuel pump switch in the
"HI" pOSition
immediately for a richer mixture while cranking.
If prolonged cranking is necessary, allow the starter motor to cool
at frequent intervals, since excessive heat may damage the armature.
TAXIING.
Taxiing over loose gravel or cinders should be done using primarily
the rpar engine. This prevents the front propeller from picking up and
throwing
particles into the rear propeller. In addition, the rear propeller
has greater ground clearance, minimizing stone damage to the propeller
Ups. Full throttle runups over loose gravel should be avoided unless the
airplane has obtained considerable forward speed.
NOTE
Taxiing, as in any twin-engine airplane, should be done
with
both engines operating.
BEFORE TAKE-OFF.
Since the engines are closely cowled for efficient in-flight cooling,
precautions should be taken to avoid overheating on the ground. Full
throttle checks on the ground are not recommended unless the pilot has
good reason to suspect that the engines are not turning up properly.
The magneto check should be made at 1800 RPM as fOllows: Move
the ignition switch first to "R" position and note RPM. Then move switch
back to "BOTH" position to clear the other set of plugs. Then move
.witch to "L" position, note RPM and return the switch to the "BOTH"
pOSition. The difference between the two magnetos operated singly should
not be more than 50 RPM. If there is a doubt concerning the operation of
the ignition system, RPM checks at a higher engine speed will usually con-
firm whether a deficiency exists.
An absence of RPM drop may be an indication of faulty grounding of
one side of the ignition system or should be cause for suspicion that the
magneto timing is set in advance of the setting specified.
To run a functional check of the battery and alternator circuits, use
the following procedure:
(1) Run both engines at 1000 RPM with some electrical equipment on.
(2) Turn front and rear alternator switches off.
(3)
The battery discharge light and front and rear alternator warning
lights should be on.
(4) Turn front alternator switch on. Both the battery discharge light
and the front alternator warning light should go out.
(5) Turn front alternator switch off following check.
(6) Turn rear alternator switch on. Both the battery discharge light
and rear alternator warning light should go out.
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