Engine Is Difficult To Start - Polaris 1999 Sportsman 400 Service Manual

40
base against the cylinder head
to
ground it. Position
the spark plug so the electrode is visible.
NOTE
/fn ot u sing a spark tester, always lise a
new spark plugjiJr this
l est
procedure.
WARNING
Mount the spar k plug, or lester, away
from the sp ar k plug hale in the cylin-
der so that the spa rk or tester ca nno t
ig nite the gasoline vapors in the
C).' / iIJ-
der.
If
the eng ine is
flooded.
do
not
p erf orm
this test.
The firing of
the
spark plug can ignite fuel
ttuu
is
ejected thro ugh the spark plug hole.
3. Tum the key. or ignition switch to the ON position.
WARNING
Do not hold the spark plug, wire or
connector.
or
a
serious electrical
shock may result.
4. Tum the engine over with the electric starter. A
crisp blue spark should be evident acro ss the spark
plug electrode or spark tester terminals. If there is
strong sunlight on the plug, shade the plug with a
hand to better see the spark.
5. Ifth e spark is good, check for one or more of the
fo llowing possible malfunctions:
a. Obstructed fuel line or fuel filter or
malf unc-
tioning fuel pump.
b. Low compres sion or engine damage.
c. Flooded eng ine.
6. If thc spark is weak or ifthere is no spark, refer to
Engine is Diffi cult to Start
in this chapter.
NO TE
If
the engine backfires during starting
attempts, the ignition timing may be
incorrect. Refer
10
Ignition Tim ing in
Chapter Three fo r more information.
ENGINE IS DIFFICULT TO START
The following section groups the three main en-
gine operating systems with probab le causes.
Electrical System
An often-o verlooked source of electrical mal-
functions is the wiring harness and electrical con-
CHAPTER TWO
nectors. Check these carefull y when troubleshoot-
mg.
I. Spa rk plug-eheck for:
a. Fouled spark plug.
b. Incorrect spark plug gap.
e. Incorrect spark plug heat range (Chapter
Three).
d. Worn or damaged spark plug electrodes.
e. Damaged spark plug.
r.
Damaged spark plug cap or secondary wire.
NOTE
Refer to Reading Sp ark Plug , ill
Chapter Three fo r additional inf or-
motion.
2. Ignition coil-eheck for:
a. Loose or damaged secondary or primary wire
leads.
b. Cracked ignition coil body.
c. Loose or corroded ground wire.
3. S. . . v itches and
wiring------check for:
a. Dirty or loose-fitting terminal s.
b. Damaged wires or connectors.
c. Damaged start switch.
d. Damaged engine auxiliary shutoff switch.
c. Damaged
key, or ignition, switch.
4. Elect rical compo llents----ehec k for:
a. Damaged CDI stator.
b. Damaged CD! unit.
Fuel System
A contaminated fuel system will cause engine
starting- and perfonnancc-rclated problems. It only
takes a small amount of dirt in the fuel valve, fuel
line or carburetor to cause problem s.