Incident Summary
During the takeoff roll, the pilot observed that the engine's revolutions per minute (RPM) began to decrease. The pilot stated that there was insufficient time to abort the takeoff and therefore continued. After liftoff, the engine RPM dropped to 1800, according to the pilot. Shortly after this additional power loss, the pilot executed a forced landing.
Examination Findings
An on-scene examination and subsequent engine test run revealed no mechanical anomalies that would cause a power loss. The mixture control was found positioned approximately 1/2 to 3/4 of an inch aft of its full forward position. The electric fuel pump was in the OFF position. A flow check was performed on the fuel injector nozzles and the fuel servo. The injector nozzles were within the manufacturer's service limits. However, the fuel servo exhibited a fuel flow rate of 22.2 pounds per hour at the idle setting. The manufacturer's specification for fuel flow at idle was between six and seven pounds per hour.
Pilot Statement
The pilot stated that the takeoff was made with the mixture control in a leaned position.