If you smell gasoline after attempting to start the
engine, the engine is probably flooded. To start a
flooded engine:
1. Move the choke lever (
Figure 3
) to the fully off
position.
2. Turn the engine stop switch to the run position
(A,
Figure 2
).
3. Open the throttle completely and press the
starter button (B,
Figure 2
). If the engine starts,
close the throttle quickly. If necessary, operate the
throttle to keep the engine running until it smoothes
out. If the engine does not start, wait 10 seconds and
then try to restart the engine by following normal
starting procedures. If the engine will not start, refer
to
Starting Difficulties
in this chapter.
STARTING DIFFICULTIES
Perform each step while remembering the engine
operating requirements described in this chapter. If
the engine still will not start, refer to the appropriate
troubleshooting procedures in this chapter.
1. Make sure the choke lever (
Figure 3
) is in the
correct position.
WARNING
Do not use an open flame to check fuel
in the tank. A serious explosion is cer
tain to result.
2. Make sure the engine stop switch (A,
Figure 2
)
moves freely and works properly. Also confirm that
the switch wire is not broken or shorting out. If nec-
essary, test the switch as described in Chapter Nine.
3. Make sure the sidestand is up and the sidestand
switch operates properly. If necessary, test the
switch as described in Chapter Nine.
4. Make sure both spark plug wires are on tight.
Push each spark plug cap and slightly rotate it to
clean the electrical connection between the plug and
the connector.
5. Test the integrity of the ignition system by per-
forming the
Spark Test
described in this section.
6. If the test produces a good spark, proceed with
Step 7. If the spark is weak or if there is no spark,
troubleshoot the ignition system as described in this
chapter.
7. Check engine compression as described in
Chapter Three. If the compression is good, perform
Step 8. If the compression is low, check for one or
more of the following:
a. Leaking cylinder head gasket(s).
b. Cracked or warped cylinder head(s).
c. Worn piston rings, pistons and cylinders.
d. Valve stuck open.
e. Worn or damaged valve seat(s).
f. Incorrect valve timing.
8. Perform the fuel pump operational test described
in Chapter Eight. If the fuel flow is good, check for
one or more of the following:
a. Clogged fuel filter or fuel line.
b. Stuck or clogged carburetor float valve.
Spark Test
The ignition spark test checks the integrity of the
ignition system. The greater the air gap that a spark
will jump, the stronger the ignition system. Use the
Yamaha Ignition Checker (part No. YM-34487 or
90890-06754), the Motion Pro Ignition System
Tester (part No. 08-122), or a similar tool (
Figure
4
) to perform this test. Connect the tester and per-
form the test as described by the tool manufac-
turer’s instructions. The ignition system is working
properly if a spark jumps a gap equal to or greater
than the ignition minimum spark gap of 6 mm (0.24
in.).
If the above equipment is not available, perform
the test with a new spark plug.
1. Remove one of the spark plugs as described in
Chapter Three.
2. Make sure the spark plug gap is correct and in-
sert the spark plug into the spark plug cap. Touch
the plug base to a good engine ground (
Figure 5
).
Position the plug so you can see the electrode.
TROUBLESHOOTING
37
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