During landing the pilot was unable to deploy the right thrust reverser. After clearing the runway, he again attempted to deploy the reverser several times. On the last attempt, the engine accessories fell off line, and a fire was reported in the tailpipe. The pilot did not receive a warning in the cockpit, but was informed by the tower. The fire continued to burn until it was suppressed by CFR personnel. The engine examination disclosed that the fuel control unit was set below the prescribed engine speed. Additionally, No.3 and No.5 carbon seals showed evidence of engine oil bypass. The right engine oil reservoir was empty, and the fire was confined to the 6 o'clock position of the engine. The fuel control was installed prior to the flight departing Little Rock. Apparently, during the rigging process the idle speed was set too low, and when the pilot cycled the thrust reverser several times a pressure difference existed over the carbon seals which allowed engine oil to pass into the tailpipe area.