I have the same problem Plane just idles down the runway. The interesting thing is. I have throttle control just after start up. But as soon as I, taxi for a bit. I Don’t get any RPM increase. With throttle full forward.
I have been able to make things work once in a while if I start at the end of the runway ready to take off. But that doesn’t always work either. Mine was an OrbX Central purchase.