Oset 16 power issue

[Redfern]

Hi, I'm after a bit of direction with a power issue on my sons 36v oset 16. 
Turned the key last night after cleaning it Sunday, throttle lights up but no power to motor. 
Controller clicks as it should when the key is turned. 
Potentiometer was looking rusty so unplugged the connetor, tried the throttle and the motor kicked but didn't run. 
Could it be a Potentiometer issue or more? 
The bike is a 16 with red frame, I've read online that these were released in 2010 and 2010 only but not too sure so don't know which Potentiometer to order!
Any help would be much appreciated, 

Thanks,

Lee.