Xray Nitro Micro NT18MT Instruction Manual - page 25
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SERVO TROUBLESHOOTING
If your micro nitro truck is performing less than optimally or is having problems, use the following troubleshooting information to attempt to determine the origin of the issue and
possible solutions. We also recommend consulting with your local hobby dealer if you encounter problems.
T ROUBLESHOOTING
If your micro nitro truck is performing less than optimally or is having problems, use the following troubleshooting information to attempt to determine the origin of the issue and
possible solutions. We also recommend consulting with your local hobby dealer if you encounter problems.
Servo makes a grinding noise or
acts erratic
Remove the servo from the truck.
Open the case and remove the gears. Examine them for broken teeth. If broken, replace with a new gear set.
Servo jitters
Remove the servo from the truck.
Open the case and remove the gears.
Spray a zero-residue electrical cleaner into and around the potentiometer and work it in.
After the cleaner has dried, re-install the gears and close the case.
Possible damaged receiver/transmitter crystal.
Servo doesn’t center properly
Disconnect the steering rod from the left front steeringblock. Steer left and right with the transmitter several times. If the servo arm does not return to the
same neutral position each time, the servo may be damaged.
Remove the servo from the truck. Open the case and check for proper gear alignment. Next check the case top for wear. If wear is evident, replace the case.
Servo is locked in place
Remove the servo from the truck.
Open the case and check for proper gear alignment. If gears are damaged, replace the gear seta
Check the case top for wear. If wear is evident, replace the case.
Servo hums
This is normal if the servo is trying to hold position against the force of a load.
If the servo hums when no load is applied, try loosening the servo case screws 1/4 to 1/2 turn.
Servo gets hot
Check the servo wiring, it should match the receiver being used.
If the wiring is okay, the servo motor may be stalled due to a failed gear train. Remove the servo from the truck, open the case and inspect for any damage.
Wheels turn in opposite direction to
setting input
Change the servo reversing setting, and then re-adjust the steering subtrim and EPA settings.
MICRO NITRO TRUCK ENGINE TROUBLESHOOTING
ENGINE SPINS BUT WILL NOT START:
• Make sure your glowplug starter is fully charged and is properly connected to the glowplug. If the starter is fully charged, replace the glowplug.
• Verify that fuel is getting to the carburetor. Remove the fuel line from the carburetor and see if there is fuel in it.
• Check your carburetor settings. It may be necessary to adjust the carburetor settings if the weather has significantly changed since the last time you ran the engine.
• The engine’s compression may be low due to wear. This will make the engine difficult to start when it is warm, and may tend to stall when running and when the throttle is
closed suddenly.
ENGINE WILL NOT SPIN (STARTER BOX WILL NOT TURN THE ENGINE):
• The engine may be flooded and hydraulically locked. Refer to section "Flooding & Hydraulic Lockup".
• 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, the piston
may be stuck at the top of the cylinder (TDC), or there could be internal engine damage. (Note: During engine break-in, it is normal for the engine to be extremely tight
and hard to turn when the piston reaches the top of the cylinder.)
ENGINE IS VERY SLUGGISH, HARD TO START, AND WILL NOT IDLE DURING INITIAL BREAK IN:
• The factory default break-in settings (on the carburetor) may be too rich for your location, weather conditions, or fuel brand. Extremes in temperature, humidity, barometric
pressure, and altitude cannot always be accounted for by the factory default settings. These symptoms may occur when air density is very low (such as in high mountains or
extremely cold temperatures. Under these conditions, lean the main needle valve slightly (1/8 turn CW), and check if there is any improvement in starting and idling. Only
lean the main needle until the engine runs and idles reliably, then continue the break-in process.
• Different fuel brands/types – in combination with extreme weather conditions – can also make the factory default break-in settings too rich and cause these symptoms. Try
leaning the fuel mixture slightly (1/8 turn CW), and check if there is any improvement in starting and idling.
ENGINE PERFORMANCE IS SLUGGISH:
• Engine performance depends on the carburetor settings and how they compensate for the weather & atmospheric conditions. Before suspecting other issues, richen the main
needle by at least 1/4 turn CCW, then retune the engine.
• Try installing a new glowplug.
• If carburetor settings are proper, ensure the fuel is fresh. Old fuel, or fuel that has been left uncapped for a long period, may cause sluggish performance.
• Verify that there is no drivetrain binding.
PISTON STUCK AT TOP OF CYLINDER – TOP DEAD CENTER (TDC):
A brand new engine that has not had a lot of break-in will typically have a very tight fit between the piston and the top of the cylinder (known as "pinch"), since the cylinder has
a tapered fit. The fit should not be so tight that then engine cannot be started. If the piston gets stuck at TDC, use a pair of pliers to grasp the flywheel from the bottom of the
engine. Rotate the flywheel CCW (viewed from the front of the engine) until the flywheel turns; you should feel the piston become unstuck from the top of the cylinder.