# SDR 2025FA0000604

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: August 25, 2025
- Submitted: September 1, 2025
- Operation: General aviation
- Aircraft: [N256Z](https://openairdocs.org/aircraft/N256Z), registered now
- Make and model: Piper PA-28-181
- Registry model: [Piper PA-28-181](https://openairdocs.org/model/piper-pa-28-181) (OpenAirDocs)
- Aircraft serial: 2881611
- Aircraft time: 1,926 hours
- System (JASC): [2820 · Aircraft Fuel Distribution System](https://openairdocs.org/jasc/2820)
- Part: Servo
- Part number: AV2581600
- Part serial: AV50937430
- Condition: Defective
- Location: Fuel Sys
- Part time: 1,926 hours
- Component: Engine, Lyc
- Component part number: IO360B4A
- Stage of operation: NR
- How discovered: 9
- Nature of condition: O
- Precautionary procedure: O
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/2025FA0000604

## Discrepancy

MOMENTARY ENGINE ROUGHNESS/VIBRATION/LOSS OF POWER. ENGINE FLUCTUATING 200-250 RPMS AT ALL RPM SETTINGS ON THE RAMP, DURING TAXI, AND DURING THE RUNUP. RAN THE ENGINE ROUGHNESS CHECKLIST WITH NO CHANGE. UNABLE TO GET A FIRM READING ON THE MAG DROP DURING RUNUP DUE TO FLUCTUATIONS SO WE RAN THE FOULED SPARK PLUG CHECKLIST WITH NO CHANGE.FUEL SERVO REPLACED.

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