There are several reasons why throttle issues may occur in the RJ Professional. This FAQ will cover the most likely causes of throttle issues in the RJ Professional and provide solutions. 

1. Firstly, please ensure that the correct control assignments are set up to control the throttles. The control assignment menu can be accessed at MSFS Options > Controls Options. If you are controlling all four throttle levers in the RJ with a single throttle lever on your external hardware, we recommend using the THROTTLE AXIS control assignment. If you have a throttle quadrant with two or more throttle levers, we recommend assigning the individual throttle axis control assignment to each lever (THROTTLE 1 AXIS, THROTTLE 2 AXIS, THROTTLE 3 AXIS, THROTTLE 4 AXIS). If you have a throttle quadrant with only 2 throttles, you may wish to assign THROTTLE 1 AXIS and THROTTLE 2 AXIS to the left throttle and THROTTLE 3 AXIS and THROTTLE 4 AXIS to the right throttle.

2. Another possible cause of the throttles not moving is due to the throttles being in the FUEL OFF position. When starting in the COLD AND DARK or TURNAROUND state, the engines will be shut down and the throttles will be in the FUEL OFF position. To move the throttles out of the FUEL OFF position, you must click the latches on the rear face of each throttle. Alternatively, the latches can be moved using various FUEL VALVE control assignments (for example, TOGGLE ENGINE 1 FUEL VALVE).

3. Users of a Thrustmaster TCA Throttle Quadrant (or similar external hardware) may experience difficulties with the throttles in the RJ due to a conflict between the way the fuel levers work on the external hardware versus the way they are set up to function in the aircraft. For users experiencing issues where only one or two throttle levers are moving, we have added the ability to reverse the fuel lever logic to suit various types of external hardware. To adjust this logic, go to the following file path:

C:\Users\**USERNAME**\AppData\Local\Packages\Microsoft.FlightSimulator_8wekyb3d8bbwe\LocalState\packages\justflight-aircraft-rj\work

At the above file path, open the JF_RJ.ini file and find the 'THE_LATCH=0' line under the [HARDWARE] heading. For users who own the Honeycomb Bravo Throttle Quadrant, we recommend leaving this line as 'THR_LATCH=0'. For users who own the Thrustmaster TCA Throttle Quadrant (or similar), we recommend updating this line to 'THR_LATCH=1'. Once the file has been saved, the change will require a restart of MSFS to take effect.

4. Finally, an A/T THROTTLE LOCK option is available on the EFB Aircraft page. With this option enabled, the throttles cannot be moved via user input when the autothrottle is engaged (A/T green on PFD). When this option is disabled, or when the autothrottle is in an armed state (A/T white on PFD) the throttles can be moved via user input. This option is intentionally set to be enabled by default and we highly recommend leaving this option enabled to prevent any user inputs or spiking in the throttle axis from interfering with the autothrottle functionality.

If the above recommendations do not fix the issue, we recommend restarting the simulator. If a restart of the simulator does not fix the issue, then this could point towards a separate activation/installation issue and we would recommend opening a ticket with Just Flight support who can assist with troubleshooting that further.