# SDR 2023FA0000265

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: May 17, 2023
- Submitted: May 17, 2023
- Operation: General aviation
- Aircraft: [N90SU](https://openairdocs.org/aircraft/N90SU), registered now
- Make and model: Cessna 172S
- Registry model: [Cessna 172S](https://openairdocs.org/model/cessna-172s) (OpenAirDocs)
- Aircraft serial: 172S8475
- Aircraft time: 7,118 hours
- Engine: Lyc IO360L2A
- Engine time: 2,491 hours
- Propeller: Mcauly 1A170E
- System (JASC): [8530 · Reciprocating Engine Cylinder Section](https://openairdocs.org/jasc/8530)
- Part: Cylinder
- Part number: LW12427
- Condition: Binding
- Part time: 264 hours
- Component: Engine, Lyc, IO360L2A
- Component part number: IO360L2A
- Stage of operation: CL
- How discovered: C
- Nature of condition: R
- Precautionary procedure: D
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/2023FA0000265

## Discrepancy

ENGINE DEVELOPED A SHUDDER EVENT ON CLIMB OUT. MOMENTARY DROP IN POWER AND RPM. RETURNED TO KOSU WITH OUT ANY OTHER ISSUES. ALL STICKING VALVES HAVE BEEN CYLINDERS #2, AND/OR #4. TECHS COMPLIED WITH LYCOMING SB N0.388C REAMED EXHAUST VALVE GUIDES. THIS CORRECTED THE ENGINE SHUDDER ISSUE.

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