It should run a little cooler if you run lower wattage. It will still generate heat after a while since you are running in FM mode. I would try to put some heat sink compound on tR51. Sometimes they skimp on that at the factory. TR51 gets warm anyway so the more heat you get away from it the more stable the radio will be. Tr51 uses the chasis for a heat sink and it is going to get warm on that side of the radio. I wish they would just put a bigger heat shink on the back of the radio with the finals and TR51. That my two cents worth anyhow good luck.