24 • NITRO 4-TEC 3.3
See Important Points to
Remember on page 4 for
other precautions.
BREAKING IN YOUR TRX 3.3 RACING ENGINE
The TRX 3.3 Racing Engine uses a ringless, aluminum-brass-chrome (ABC)
piston/sleeve construction. This type of engine design relies on a very
precise running fit between the piston and sleeve for cylinder sealing.
Engine break-in is necessary to allow the piston and sleeve to develop
an extremely precise fit and optimum cylinder sealing. Therefore,
proper engine break-in is critical to achieving the fastest, most reliable
engine performance.
Allow yourself about 1 to 1
½
hours to complete the break-in procedure. The
engine break-in period will take 5 tanks of fuel in a Nitro 4-Tec. The break-in
time is not the time to impress your friends with your new Nitro 4-Tec.
You
must wait until the engine is fully broken in before attempting sustained
high speed running.
Patience and careful attention during break-in will
reward you with the best-performing TRX 3.3 Racing Engine possible.
During break-in, your engine may appear to malfunction with symptoms
like stalling, inconsistent performance, and fouled glow plugs. These are
simply the normal “break-in pains” engines sometimes go through. They
will disappear once your engine is fully broken in. Many owners report
not experiencing any of these symptoms with TRX Racing Engines.
We
recommend replacing the glow plug with a new one (included) after the
engine break in procedure.
Use the supplied glow plug wrench to remove
the glow plug from the engine’s cylinder head (see page 15).
Engine Break-in Procedure
The focus during break-in is to vary and limit the engine speed. This will be
accomplished by accelerating and stopping at different rates for the first 5
tanks of fuel. As the engine begins to break-in, the duration and intensity
of the acceleration will gradually increase.
Sustained high-speed running
is not permitted until the 6th tank of fuel.
Perform the initial break-in on a
large, flat, paved surface.
Nitro 4-Tec is very fast and by tanks 4 and 5 you
will need plenty of room for the model to run in. Apply all throttle and
braking actions gently. Abrupt acceleration or braking could cause the
engine to stall unnecessarily.
• Special break-in fuels are not recommended. Use the same fuel you plan
to use everyday.
• If possible, avoid breaking-in the engine on extremely hot or cold days
(see page 26).
• Pay careful attention to the fuel level. Do not allow the fuel tank to run
completely empty. An extremely low fuel level causes the mixture to run
too lean. This could result in a burned glow plug or extremely high engine
temperatures.
• Change or clean your air filter after break-in.
•
Do not attempt to break in the TRX 3.3 Racing Engine by idling it on a
stand. This will produce poor results.
• Keep extra Traxxas glow plugs handy. The break-in process can cause
deposits to form on the plug leading to plug failure.
• Follow the instructions exactly for each of the first 5 tanks of fuel.
Starting Your TRX 3.3 Racing Engine for the First Time
Before you start your TRX 3.3 Racing Engine for the first time, make sure
you have read all instructions and precautions in this manual.
Pay close
attention to the tank-by-tank break-in instructions in the next section,
and make sure you have read and understood them before you run
your engine.
Your engine must be at room temperature (70°F or 21° C) or above the
first time you start it
. If it’s cooler than room temperature outside, remove
all fuel and keep your Nitro 4-Tec indoors until you’re ready to start it and
then take it outside. If it’s colder than 45°F, special considerations should
be made. See cold weather break-in on page 26. We do not recommend
running the model in temperatures below 35°F.
1.
Turn on the radio system
(see page 11).
2. Make sure the throttle trigger on the
transmitter is in the idle (neutral) position.
3. Connect the EZ-Start controller according to
the instructions on page 22.
4. Press the starter button in short two-second
bursts and watch for fuel moving through the
fuel line up to the carburetor. Watch closely! The fuel moves very fast.
If the fuel doesn’t move through the line within 5 seconds, prime the
engine by briefly (one or two seconds) covering the exhaust outlet
with your finger and pressing the EZ-Start button until the fuel is just
visible in the carburetor fuel line.
Watch carefully! If the engine is
primed too long, it will flood with fuel and stop turning.
5. Once fuel reaches the carburetor, the engine should
quickly start and idle.
6. Disconnect the EZ-Start controller from the model.
7. Proceed with the engine break-in.
8. Do not rev your engine with no load (wheels off the ground).
If your engine doesn’t start, go online to Traxxas.com/support. If your
factory fuel mixture settings have been altered, refer to page 21. If you
still have problems, contact Traxxas Customer Support at 1-888-TRAXXAS
or [email protected].
Never run your Nitro 4-Tec
indoors. Since the TRX 3.3
Racing Engine exhaust fumes
are harmful, always run your
model outdoors, in a well-
ventilated area.
Your TRX 3.3 Racing Engine
doesn’t usually require priming.
If you do need to prime your
engine, watch the fuel line
carefully to avoid flooding
your engine. See page 34 for
information on clearing a
flooded engine.
Factory Needle Settings:
Your carburetor is preset at
the factory to give the correct
air-to-fuel ratio and idle speed
for engine break-in. Do not
adjust the carburetor unless
you observe a poor running
condition that requires
correction (see page 21 for
stock settings).
Higher nitro requires a richer
fuel mixture. When running
33% fuel, richen your high-
speed needle 3/4 turn if
previously running 20% nitro
and then re-tune the engine
for maximum performance. See
page 18 for more information.
THE TRX 3.3 RACING ENGINE
12,13
