The output of the baseboard varies with temp, but it still puts out quite a bit of heat even with 115F water, but clearly you need a higher temp if the room isn't being brought up to temp.
The problem isn't the pump, it's either the boiler's settings, or a mixer valve that had been mixing down the boiler's output with return water from radiation. I assume you've purged the air in the system and it's getting a reasonable amount of flow, and that the 115F temp is measured at the boiler, not at the baseboard?
If it's not a modulating/condensing boiler running it at 115F for extended periods will damage the heat exchangers, and may shorten it's life to less than one full heating season. What boiler name/model is it?