I have a 2006 asv rc50. It runs well. If I’m moving at full speed and move the bucket at full speed. It will big down the motor. If I don’t back off of something, it will kill the motor eventually. I know my controls are getting worn because when it’s cold the machine doesn’t respond precisely to the controls. A little temp and then it’s fine. I don’t know if that’s related or not. Ideas???
I would start with the basics, check air filter, change fuel filters etc... I solved a PT50 (newer model but basically the same) with a similar problem. Turned out to be the primary fuel filter head was cracked, allowing air to enter the system. As for the controls, check the charge pressure. Test port is beside the fuel filter. 400-450 psi Hope this helps Stay safe