The pilot was conducting a flight in the local training area. He reported that as he applied power to climb from 2000 to 3000 feet amsl the engine suddenly stopped completely. Efforts to regain power were unsuccessful and during the ensuing forced landing the right wing struck a dead tree. A piece of silastic material was found to be blocking the main discharge tube of the carburettor. Spectroscopic analysis indicated that the silastic was similar to that used to seal the radio inspection hatch against water ingress. It was probable that when the hatch was opened for radio maintenance some of the sealing compound fell into the engine area below. Maintenance records revealed that the carburettor bowl was removed for repair on the day preceding the accident, however it could not be positively determined whether the silastic entered the carburettor on this, or on some other occasion.
