TRX 2.5R • 22
TUNING THE TRX 2.5R
• Wrap the cooling head with a paper towel, clean rag or sock to help keep the engine running at
the recommended 200 to 215 break-in temp. If too much heat is contained, the engine may run
too hot. Make sure that you monitor the engine's temp closely for the first couple of tanks until
you get the right amount of cover for the cooling head. This will, of course, depend on your
current weather conditions. Adjusting the cover up and down, exposing more or fewer cooling
fins, is a convenient way to regulate engine temps.
• For owners that do not have access to a temperature probe, a drop of water on the cooling head
(around the glow plug area) should slowly sizzle for approximately 6 to 8 seconds when the
engine temp is 200 to 210 degrees. If the water sizzles for only a few seconds, then it is likely that
the engine temp is over 220 degrees and needs to cool down. If the water takes a long time or
does not evaporate at all, then the engine is too cool.
• We do not recommend that you operate your engine below 35 degrees Fahrenheit. If you insist
on running your vehicle below 35 degrees, be aware that nitro engines may be very difficult to
start and tune at those extremely cold temperatures. Also, at temperatures below freezing, nitro
fuel can actually begin to gel up, and this can be harmful to the engine.
• Follow the remaining break-in procedures as outlined in this owner's manual. This, along with the
steps listed above, will ensure a good break-in for your new nitro engine and provide many hours
of enjoyment.
Tuning Your TRX 2.5R Racing Engine
The engine’s performance depends on the fuel mixture. Turn the mixture needles clockwise to
lean the fuel mixture and counterclockwise to richen it. Leaning the fuel mixture will increase
engine power up to the engine’s mechanical limits.
Never run the engine too lean (not
enough fuel flow). Never lean the engine until it begins to cut-out or stall.
Leaning the
engine beyond the safe allowable limits will result in poor performance and almost certain
engine damage.
Indications of an overly lean mixture include:
•
Cutting out or sudden loss of power during acceleration.
• Overheating (temperature beyond 270° F at the glow plug)
• Little or no blue smoke coming from the exhaust.