PA30 PLT HAS A MALFUNCTIONING R ENG; DECLARES AN EMER AND RETURNS FOR LNDG.

Narrative

TKOF AND CLBOUT WERE NORMAL; AND AT 500 FT I SWITCHED TO THE AUX TANKS (WHICH WERE FULL); SECURED THE AUX (ELECTRIC) FUEL PUMPS AND REDUCED TO CLB PWR (25 MP AND 2600 RPM). APPROX 2 MINS LATER AS I WAS LEVELING AT 2000 FT 5-6 NM S OF ZZZ THE R ENG BEGAN TO RUN ROUGH. I BEGAN TROUBLESHOOTING; AND NOTED THAT FUEL FLOW; FUEL PRESSURE; OIL TEMP AND OIL PRESSURE ON BOTH ENGS WERE WITHIN NORMAL LIMITS. ALTHOUGH THE R ENG WAS STILL MAKING PARTIAL PWR; SINCE EXTENSIVE MAINT HAD BEEN PERFORMED ON THAT ENG'S FUEL SYS I WAS CONCERNED ABOUT POSSIBLE FUEL LEAKS; AND ALSO CONCERNED ABOUT DAMAGING THE ENG FURTHER; SO I VERIFIED THE BAD ENG; THEN FEATHERED AND SECURED IT AS PER THE CHKLIST. I CALLED APCH CTL AND DECLARED AN EMER; STATING THAT I HAD FEATHERED MY R ENG AND THAT I INTENDED TO RETURN TO ZZZ; THE CLOSEST ARPT. THE CTLR CLRED ME DIRECTLY TO THE FIELD AND SWITCHED ME TO THE TWR. THE TWR CTLR ASKED FOR SOULS AND FUEL ON BOARD (1 SOUL ON BOARD; 2 HRS FUEL REMAINING AT NORMAL CRUISE; BOTH ENGS OPERATING) AND OFFERED ME ANY RWY FOR LNDG. I ELECTED TO MAKE A NORMAL VFR APCH; XING MIDFIELD AT 2000 FT FOR A L DOWNWIND ENTRY TO RWY 10L. I FELT THAT FLYING A STANDARD TFC PATTERN WOULD BE SAFER THAN TAKING UNUSUAL MEASURES TO LAND IMMEDIATELY. THE APCH AND LNDG WERE ENTIRELY NORMAL; AND I TAXIED TO THE FBO AND SHUT DOWN. NO EXTERNAL DAMAGE OR FUEL LEAKS WERE NOTED.