Hydramaster cds 4.8 not revving above 1300 rpms

[r newbern]

I purchased a used cds machine yesterday its 2011 40k miles cds has just over 1000hrs, the machine won't get over 1300rpms, in either switch position, I tried to adjust the adjuster screws on box under dash that didn't change anything, I noticed that the lights on box are all working none are blinking and stay lit , says park brake is good, however when switch positions it reads on box lights ,1 rpm light is lit when on high speed and 2 speed is correct and on low speed rpm3 is lit. I checked wiring and looks OK compared to diagram in manual Any recommendations would be greatly appreciated

 

[Bryce C]

I purchased a used cds machine yesterday its 2011 40k miles cds has just over 1000hrs, the machine won't get over 1300rpms, in either switch position, I tried to adjust the adjuster screws on box under dash that didn't change anything, I noticed that the lights on box are all working none are blinking and stay lit , says park brake is good, however when switch positions it reads on box lights ,1 rpm light is lit when on high speed and 2 speed is correct and on low speed rpm3 is lit. I checked wiring and looks OK compared to diagram in manual Any recommendations would be greatly appreciated

That's weird. Maybe it is a faulty throttle controller.