On June 30, 1994, at 1220 central daylight time, a Piper J4A, N30342, was substantially damaged during a forced landing. The commercial pilot was not injured. Visual meteorological conditions prevailed for the local maintenance test flight. The pilot reported that the number two and four cylinders were changed on the engine. Prior to flight no discrepancies were found during a ground operational test run of the engine. During the takeoff initial climb 300 feet above the ground, a total loss of engine power occurred. The airplane was approximately 1/4 mile beyond the departure end of the runway where the land merged with water. A street was selected for the landing. During the landing roll the left wing struck a tree. The Federal Aviation Administration inspectors' examination of the airplane at the accident site revealed the fuel primer control was unlocked and out one half inch. A test run of the engine with the primer in did not disclose any discrepancies.