Flight Training - June 2020 - 15

HOW IT WORKS

BY KOLLIN STAGNITO

PRIMER

THE COLD START REMEDY
WHEN COLD, A CARBURETED AIRCRAFT ENGINE MAY NOT GENERATE SUFFICIENT HEAT

to vaporize the fuel in its cylinders, resulting in an engine that won't start. A manual
fuel primer injects vaporized fuel directly into one or more of the engine's cylinders to
aid in starting. Fuel-injected engines do not require a primer.
The primer knob is typically located on the instrument panel and is locked in the
closed position. To unlock the primer, twist while gently pulling back on the primer
knob until it unlocks. Slowly pull the primer knob all the way out, and allow the primer
to fill with fuel drawn from the fuel sump. Slowly push the primer knob all the way in
to force fuel through small fuel lines and special nozzles that create a fine mist as it is
injected directly into the engine cylinders. When completed, lock the primer by pushing it fully in and rotating the knob a quarter turn. Confirm the primer is locked by
pulling on it to make sure it does not move. A primer accidentally left open will cause
the engine to run rough after starting.
Check your aircraft's pilot's operating handbook (POH) for proper cold and hot
starting procedures, but two "pumps" of the primer are typically used to prime the
engine before the first start of the day. Some POHs recommend against priming an
already warm engine.

EASY DOES IT
When more is not better

Pumping the primer too
many times can lead to
overpriming the engine.
This can cause excess fuel
to be sprayed into the
engine cylinder, which
can drip onto the exhaust
manifold and result in a fire
when starting. If you smell
fuel when priming, stop-
you may have overprimed
the engine. Consult your
pilot's operating handbook
for the correct procedures
to follow for a flooded or
overprimed engine.

kollin.stagnito@aopa.org

Engine cylinder

STEVE KARP

Fuel sump

Primer
knob

AOPA.ORG/FT

15


http://www.AOPA.ORG/FT

Flight Training - June 2020

Table of Contents for the Digital Edition of Flight Training - June 2020

Contents
Flight Training - June 2020 - Intro
Flight Training - June 2020 - Cover1
Flight Training - June 2020 - Cover2
Flight Training - June 2020 - Contents
Flight Training - June 2020 - 2
Flight Training - June 2020 - 3
Flight Training - June 2020 - 4
Flight Training - June 2020 - 5
Flight Training - June 2020 - 6
Flight Training - June 2020 - 7
Flight Training - June 2020 - 8
Flight Training - June 2020 - 9
Flight Training - June 2020 - 10
Flight Training - June 2020 - 11
Flight Training - June 2020 - 12
Flight Training - June 2020 - 13
Flight Training - June 2020 - 14
Flight Training - June 2020 - 15
Flight Training - June 2020 - 16
Flight Training - June 2020 - 17
Flight Training - June 2020 - 18
Flight Training - June 2020 - 19
Flight Training - June 2020 - 20
Flight Training - June 2020 - 21
Flight Training - June 2020 - 22
Flight Training - June 2020 - 23
Flight Training - June 2020 - 24
Flight Training - June 2020 - 25
Flight Training - June 2020 - 26
Flight Training - June 2020 - 27
Flight Training - June 2020 - 28
Flight Training - June 2020 - 29
Flight Training - June 2020 - 30
Flight Training - June 2020 - 31
Flight Training - June 2020 - 32
Flight Training - June 2020 - 33
Flight Training - June 2020 - 34
Flight Training - June 2020 - 35
Flight Training - June 2020 - 36
Flight Training - June 2020 - 37
Flight Training - June 2020 - 38
Flight Training - June 2020 - 39
Flight Training - June 2020 - 40
Flight Training - June 2020 - 41
Flight Training - June 2020 - 42
Flight Training - June 2020 - 43
Flight Training - June 2020 - 44
Flight Training - June 2020 - 45
Flight Training - June 2020 - 46
Flight Training - June 2020 - 47
Flight Training - June 2020 - 48
Flight Training - June 2020 - 49
Flight Training - June 2020 - 50
Flight Training - June 2020 - 51
Flight Training - June 2020 - 52
Flight Training - June 2020 - 53
Flight Training - June 2020 - 54
Flight Training - June 2020 - 55
Flight Training - June 2020 - 56
Flight Training - June 2020 - Cover3
Flight Training - June 2020 - Cover4
https://www.nxtbook.com/nxtbooks/aopa/ft_202107
https://www.nxtbook.com/nxtbooks/aopa/ft_202106
https://www.nxtbook.com/nxtbooks/aopa/ft_202104
https://www.nxtbook.com/nxtbooks/aopa/ft_202105
https://www.nxtbook.com/nxtbooks/aopa/ft_202103
https://www.nxtbook.com/nxtbooks/aopa/ft_202101
https://www.nxtbook.com/nxtbooks/aopa/ft_202011
https://www.nxtbook.com/nxtbooks/aopa/ft_202009
https://www.nxtbook.com/nxtbooks/aopa/ft_202008
https://www.nxtbook.com/nxtbooks/aopa/ft_202007
https://www.nxtbook.com/nxtbooks/aopa/ft_202006
https://www.nxtbook.com/nxtbooks/aopa/ft_202005
https://www.nxtbook.com/nxtbooks/aopa/ft_202004
https://www.nxtbook.com/nxtbooks/aopa/ft_202003
https://www.nxtbook.com/nxtbooks/aopa/ft_202001
https://www.nxtbook.com/nxtbooks/aopa/ft_201912
https://www.nxtbook.com/nxtbooks/aopa/ft_201911
https://www.nxtbook.com/nxtbooks/aopa/ft_201910
https://www.nxtbook.com/nxtbooks/aopa/ft_201909
https://www.nxtbook.com/nxtbooks/aopa/ft_201908
https://www.nxtbook.com/nxtbooks/aopa/ft_201907
https://www.nxtbook.com/nxtbooks/aopa/ft_201906
https://www.nxtbook.com/nxtbooks/aopa/ft_201905
https://www.nxtbook.com/nxtbooks/aopa/ft_201904
https://www.nxtbook.com/nxtbooks/aopa/ft_201903
https://www.nxtbook.com/nxtbooks/aopa/ft_201902
https://www.nxtbook.com/nxtbooks/aopa/ft_201901
https://www.nxtbook.com/nxtbooks/aopa/ft_201812
https://www.nxtbook.com/nxtbooks/aopa/ft_201811
https://www.nxtbook.com/nxtbooks/aopa/ft_201810
https://www.nxtbook.com/nxtbooks/aopa/ft_201809
https://www.nxtbook.com/nxtbooks/aopa/ft_201808
https://www.nxtbook.com/nxtbooks/aopa/ft_201807
https://www.nxtbook.com/nxtbooks/aopa/ft_201806
https://www.nxtbook.com/nxtbooks/aopa/ft_201805
https://www.nxtbook.com/nxtbooks/aopa/ft_201804
https://www.nxtbook.com/nxtbooks/aopa/ft_201803
https://www.nxtbook.com/nxtbooks/aopa/ft_201802
https://www.nxtbook.com/nxtbooks/aopa/ft_201801
https://www.nxtbook.com/nxtbooks/aopa/ft_201712
https://www.nxtbook.com/nxtbooks/aopa/ft_201711
https://www.nxtbook.com/nxtbooks/aopa/ft_201710
https://www.nxtbook.com/nxtbooks/aopa/ft_201709
https://www.nxtbook.com/nxtbooks/aopa/ft_201708
https://www.nxtbook.com/nxtbooks/aopa/ft_201707
https://www.nxtbook.com/nxtbooks/aopa/ft_201706
https://www.nxtbook.com/nxtbooks/aopa/ft_201705
https://www.nxtbook.com/nxtbooks/aopa/ft_201704
https://www.nxtbook.com/nxtbooks/aopa/ft_201703
https://www.nxtbook.com/nxtbooks/aopa/ft_201702
https://www.nxtbook.com/nxtbooks/aopa/ft_201701
https://www.nxtbook.com/nxtbooks/aopa/ft_201612
https://www.nxtbook.com/nxtbooks/aopa/ft_201611
https://www.nxtbook.com/nxtbooks/aopa/ft_201610
https://www.nxtbook.com/nxtbooks/aopa/ft_201609
https://www.nxtbook.com/nxtbooks/aopa/ft_201608
https://www.nxtbook.com/nxtbooks/aopa/ft_201607
https://www.nxtbook.com/nxtbooks/aopa/ft_201606
https://www.nxtbook.com/nxtbooks/aopa/ft_201605
https://www.nxtbook.com/nxtbooks/aopa/ft_201604
https://www.nxtbook.com/nxtbooks/aopa/ft_201603
https://www.nxtbook.com/nxtbooks/aopa/ft_201602
https://www.nxtbook.com/nxtbooks/aopa/ft_201601
https://www.nxtbook.com/nxtbooks/aopa/ft_201512
https://www.nxtbook.com/nxtbooks/aopa/ft_201511
https://www.nxtbook.com/nxtbooks/aopa/ft_201510
https://www.nxtbook.com/nxtbooks/aopa/ft_201509
https://www.nxtbook.com/nxtbooks/aopa/ft_201508
https://www.nxtbook.com/nxtbooks/aopa/ft_201507
https://www.nxtbook.com/nxtbooks/aopa/ft_201506
https://www.nxtbook.com/nxtbooks/aopa/ft_201505
https://www.nxtbook.com/nxtbooks/aopa/ft_201504
https://www.nxtbook.com/nxtbooks/aopa/ft_201503
https://www.nxtbook.com/nxtbooks/aopa/ft_201502
https://www.nxtbook.com/nxtbooks/aopa/ft_201501
https://www.nxtbook.com/nxtbooks/aopa/ft_201412
https://www.nxtbook.com/nxtbooks/aopa/ft_201411
https://www.nxtbook.com/nxtbooks/aopa/ft_201410
https://www.nxtbook.com/nxtbooks/aopa/ft_201409
https://www.nxtbook.com/nxtbooks/aopa/ft_201408
https://www.nxtbook.com/nxtbooks/aopa/ft_201407
https://www.nxtbook.com/nxtbooks/aopa/ft_201406
https://www.nxtbook.com/nxtbooks/aopa/ft_201405
https://www.nxtbook.com/nxtbooks/aopa/ft_201404
https://www.nxtbook.com/nxtbooks/aopa/ft_201403
https://www.nxtbook.com/nxtbooks/aopa/ft_201402
https://www.nxtbook.com/nxtbooks/aopa/ft_201401
https://www.nxtbook.com/nxtbooks/aopa/ft_201312
https://www.nxtbook.com/nxtbooks/aopa/ft_201311
https://www.nxtbook.com/nxtbooks/aopa/ft_201310
https://www.nxtbook.com/nxtbooks/aopa/ft_201309
https://www.nxtbook.com/nxtbooks/aopa/ft_201308
https://www.nxtbook.com/nxtbooks/aopa/ft_201307
https://www.nxtbook.com/nxtbooks/aopa/ft_201306
https://www.nxtbook.com/nxtbooks/aopa/ft_201305
https://www.nxtbook.com/nxtbooks/aopa/ft_201304
https://www.nxtbook.com/nxtbooks/aopa/ft_201303
https://www.nxtbook.com/nxtbooks/aopa/ft_201302
https://www.nxtbook.com/nxtbooks/aopa/ft_201301
https://www.nxtbook.com/nxtbooks/aopa/ft_201212
https://www.nxtbook.com/nxtbooks/aopa/ft_201211
https://www.nxtbook.com/nxtbooks/aopa/ft_201210
https://www.nxtbook.com/nxtbooks/aopa/ft_201209
https://www.nxtbook.com/nxtbooks/aopa/ft_201208
https://www.nxtbook.com/nxtbooks/aopa/ft_201207
https://www.nxtbook.com/nxtbooks/aopa/ft_201206
https://www.nxtbook.com/nxtbooks/aopa/ft_201205
https://www.nxtbook.com/nxtbooks/aopa/ft_201204
https://www.nxtbook.com/nxtbooks/aopa/ft_201203
https://www.nxtbook.com/nxtbooks/aopa/ft_201202
https://www.nxtbook.com/nxtbooks/aopa/ft_201201
https://www.nxtbook.com/nxtbooks/aopa/ft_201112
https://www.nxtbook.com/nxtbooks/aopa/ft_201111
https://www.nxtbook.com/nxtbooks/aopa/ft_201110
https://www.nxtbook.com/nxtbooks/aopa/ft_201109
https://www.nxtbook.com/nxtbooks/aopa/ft_201108
https://www.nxtbook.com/nxtbooks/aopa/ft_201107
https://www.nxtbook.com/nxtbooks/aopa/ft_201106
https://www.nxtbook.com/nxtbooks/aopa/ft_201105
https://www.nxtbook.com/nxtbooks/aopa/ft_201104
https://www.nxtbook.com/nxtbooks/aopa/ft_201103
https://www.nxtbookmedia.com