Please let us know how it goes and we will take it from there.
The No Load reading should be around 27 Volts, and the Under Load reading should be above 23 Volts. If the Under Load reading is 23 Volts or less then the battery pack is old, worn out, damaged, or faulty and will need to be replaced. The Crazy Cart's controller will not allow the motor to run when the Voltage is 23 Volts or less.
Please let us know how it goes.