Your pump has two speeds. The spa should heat on the low speed. If you are running the jets continually, with the pump on high speed, then it is normal for the tub to overheat.
You need to find a setting where the jet pump runs on low speed, controlled by the setting of the thermostat. There may be a time delay: turn the jets off, set the thermostat for 102, and wait for ten minutes.
Stuart will be along shortly, so find out the year and model of tub you have so he doesn't have to ask...