24 • T-MAXX
See Important Points to
Remember on page 4 for other
precautions.
BREAKING IN YOUR TRX 2.5 RACING ENGINE
The TRX 2.5 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 T-Maxx. The break-
in time is not the time to impress your friends with your new T-Maxx.
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 2.5 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.
T-Maxx is very fast and
by tanks 4 and 5 you will need plenty of room for the truck 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.
•
Do not attempt to break in the TRX 2.5 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.
• Change or clean your air filter after break-in.
• Follow the instructions exactly for each of the first 5 tanks of fuel.
Starting Your TRX 2.5 Racing Engine for the First Time
Before you start your TRX 2.5 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 T-Maxx 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, refer to the troubleshooting tips on page 35 or
go online to www.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 T-Maxx
indoors. Since the TRX 2.5
Racing Engine exhaust fumes
are harmful, always run your
model outdoors, in a well-
ventilated area.
Your TRX 2.5 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 2.5 RACING ENGINE
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