User's Manual

NITRO 4-TEC 3.3
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35
The following section addresses some very basic engine questions
you may have about your Nitro 4-Tec 3.3. Most questions arise from
simple user errors or minor adjustments that are easy to correct.
If you can’t find a solution for your Nitro 4-Tec here, then visit our
Web site at Traxxas.com and click on the Customer Support menu.
There you will find a much more extensive and detailed online
troubleshooting area. In addition, you may call Traxxas Customer
Service at 1-888-TRAXXAS (outside the US call 972-265-8000).
Engine will not spin (EZ-Start will not turn the engine):
If neither LED on the controller lights, the EZ-Start battery could
be discharged or improperly connected. Inspect and recharge if
necessary.
If the glow plug LED lights and the motor LED does not, then the
EZ-Start controller is in protection mode. Allow the controller to cool
for at least three minutes. The circuitry should automatically reset.
Check to make sure the wires are connected to the EZ-Start motor
in the Nitro 4-Tec. The red wire should connect to the positive
motor terminal, indicated by a red dot next to the terminal.
The engine could be flooded. If too much fuel accumulates in the
combustion chamber at start up, the engine will hydraulically lock.
Follow the procedure on page 34 for clearing a flooded engine.
Check for binding at the engine flywheel. If you are not able to
turn the engine by hand, the engine could be flooded, there
could be binding in the clutch system, or there could be internal
engine damage. See page 34 for info on clearing a flooded
engine and releasing a stuck piston. (Note: It is normal for the
engine to be extremely tight and hard to turn when the piston
reaches the top of the compression stroke.)
Engine spins but will not start:
If the engine is spinning but will not start, first check to make sure
that both the motor and glow plug LEDs on the EZ-Start controller
light when the button is depressed. If the glow plug LED does not
light, make sure the blue glow plug wire is tightly connected and is
not damaged in any way. If the wire is good, then replace the glow
plug. It is normal for glow plugs to require periodic replacement.
Only use Traxxas heavy-duty long glow plugs (part #3231).
Check to make sure the fuel is getting to the carburetor. Remove the
fuel line where it connects to the carburetor to see if there is fuel in it.
If not, you may need to prime the engine. Reconnect the fuel line and
then refer to page 24 for instructions on priming the engine.
Check your fuel mixture settings. It may be necessary to adjust
the fuel mixture if the outside temperature or barometric pressure
has changed significantly since the last time the engine was run
(see Fine Tuning the Carburetor on page 28). Turn the high-speed
needle out (rich/counterclockwise) 1/4 turn, hold the throttle
trigger at about 1/2 throttle and try again to start the engine.
Once started, retune the engine for performance (see page 26).
The engine could be worn. If the fit between the piston and
sleeve is loose, compression is reduced and the engine will be
difficult to start when it is warm, and may tend to stall when
running and when the throttle is closed suddenly to idle. Engine
life depends on many factors including fuel type, air filter
maintenance, needle settings, and how the engine was used.
For example, if the engine was allowed to ingest dirt from lack
of air filter maintenance or running through water, then the
internal engine components could wear out extremely fast.
Engine extremely sluggish, hard to start, and will not idle
during tank 1 of the break in:
It is possible that the factory adjusted break-in settings on
your carburetor are too rich for your geographic location,
atmospheric conditions, or fuel brand. Extremes in temperature,
humidity, barometric pressure, and altitude can’t always be
accounted for with a single high-speed needle setting. The
symptoms described above can occur when the air density is
very low such as in high mountainous elevations, and extremely
cold temperatures. Under these conditions, lean the fuel mixture
slightly, 1/8 turn, to see if there is any improvement in starting
and idling. Only lean the fuel mixture just until the engine will
run and idle reliably and then proceed with the break in.
The contents of different brands of fuel (other than Traxxas Top Fuel)
in combination with extreme atmospheric conditions can also make
the factory preset break-in settings too rich and cause the symptoms
described above. Again, try leaning the fuel mixture slightly, 1/8 turn,
to see if there is any improvement in starting and idling.
Engine performance sluggish:
Engine performance depends mostly on the fuel mixture
settings and how they compensate for the current atmospheric
conditions. Before you suspect other failures with the engine,
richen the high-speed needle at least 1/4 turn and then retune
the engine for performance (see page 26).
Try a new Traxxas 3231 glow plug. Sometimes a glow plug will
work well enough to start the engine but not be able to deliver
the engine’s full performance potential.
If the fuel mixture seems to be set correctly, make sure the
fuel is fresh. If the fuel is old, or was left uncapped for a long
period, then some of the important fuel components could have
evaporated. Try new, fresh, Traxxas Top Fuel
Check to make sure there is no binding in the driveline that
would cause excessive loads on the engine.
TROUBLESHOOTING YOUR NITRO 4-TEC 3.3