Cessna 182S Pilot Operating Handbook page 418

CESSNA
MODEL 182S
BEFORE TAKEOFF
WARM UP
SECTION 4
NORMAL PROCEDURES
I
If the engine idles (approximately 650 RPM) and accelerates
smoothly, the airplane is ready for takeoff, Since the engine is
closely cowled for efficient in-flight cooling, precautions should be
taken to avoid overheating during prolonged engine operation on
the ground, Also, long periods of idling may cause fouled spark
plugs,
MAGNETO CHECK
The magneto check should be made at 1800 RPM as follows,
Move ignition switch first to R position and note RPM, Next move
switch back to BOTH to clear the other set of plugs, Then move
switch to the L position, note RPM and return the switch to the
BOTH position, RPM drop should not exceed 150 RPM on either
magneto or show greater than 50 RPM differential between
magnetos, If there is a doubt concerning operation of the ignition
system, RPM checks at higher engine speeds will usually confirm
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,
ALTERNATOR CHECK
Prior to flights where verification of proper alternator and
alternator control unit operation is essential (such as night or
instrument flights), a positive verification can be made by loading
the electrical system momentarily (3 to 5 seconds) with the landing
light or by operating the wing flaps during the engine runup (1800
RPM), The ammeter will remain within a needle width of its initial
reading if the alternator and alternator control unit are operating
properly,
Nov
1/01 4-23