On November 23, 1994, at 1630 eastern standard time, N4430P, a Piper PA-23-160, piloted by the commercial pilot/registered owner, experienced a loss of engine power and crashed in a swamp 10 miles southeast of Cherry Ridge Airport in Blooming Grove, Pennsylvania. The commercial pilot and the one passenger, the sole occupants, received minor injuries. The airplane was substantially damaged. Instrument meteorological conditions prevailed and an instrument flight rules (IFR) flight plan was filed. The airplane operated under 14 CFR Part 91. The flight originated in Louisville, Kentucky at 1306, with an intended destination of Poughkeepsie, New York. The pilot reported that the airplane was in cruise flight in clouds at 9000 feet Mean Sea Level (MSL) when it encountered a snow squall. He stated that when he applied carburetor heat to both engines, the right carburetor heat control worked properly, but the carburetor heat control for the left engine would only move 1/3 of its normal travel. In an attempt to get clear of the clouds, the pilot requested and received Air Traffic Control (ATC) clearance to climb to 11,000 feet MSL. The pilot stated when he reached 11,000 feet, the airplane was still in the clouds, and had accumulated 1/2 inch of rime ice. In another attempt to get clear of the clouds, the pilot requested ATC clearance to deviate to the east of his intended flight path. ATC was unable to accommodate that request, but approved a subsequent request to descend to 5,000 feet MSL. The pilot stated that at 5,000 feet, the carburetor heat control for the left engine "...freed up..." however the left engine "...failed to produce thrust...aircraft would not maintain 5,000 MSL...I requested vectors to the nearest airport." The pilot stated that he was unable to maintain altitude on one engine, and as the airplane descended, the right engine lost power. The pilot made a forced landing in a swamp. The airplane was examined at the accident site by an FAA Aviation Safety Inspector. The examination included the removal of the spark plugs. The examination revealed water in the cylinders of both engines. At the time of the accident there was snow showers in the area. The pilot reported that there was no mechanical malfunction, and that he had received two weather briefings. He also reported that the accident could have been prevented if the route of flight was further eastward so as to avoid the cold front with lake effects snow. At 1653, the Wilkes-Barre/Scranton, Pennsylvania Weather Observation Facility, located 23 nautical miles west of the accident site, recorded a temperature of 27 degrees Fahrenheit and a dew point of 24 degrees Fahrenheit. According to Icing Probability Curves, conditions which are known to be favorable to the formation of moderate induction system icing at glide power existed. (See attached Icing Probablity Curve Chart.)