Incident Overview
Shortly after takeoff, the pilot reported that the airplane's engine stopped and then restarted. Soon after, the engine began to lose power again, prompting the pilot to execute a forced landing. The aircraft was subsequently inspected to determine the cause of the power loss.
Inspection Findings
During the inspection, it was discovered that one spark plug in each of cylinders number 1, 4, 5, and 6 was only 'finger' tight. Additionally, the second spark plug in cylinder number 6 had completely separated from the cylinder. These spark plugs had been removed by a mechanic for a pre-buy inspection prior to the pilot's purchase of the airplane.
Conclusion
The investigation did not provide a stated probable cause. The source only documented the pilot's account and the mechanical findings.