Performed 100 hour inspection on ENGINE. Compressions #1: 80/80, #2: 80/80, #3: 80/80, #4: 80/80. Removed, cleaned, inspected, tested, and gapped spark plugs to spec. Removed, cut open and inspected oil filter. No defects found. Drained oil and serviced with 7qts. Aeroshell W100 Plus. Lubricated controls. De-greased engine. Re-secured alternator belt. All work done in reference to Cessna 172 MM, Lycoming Overhaul Manual, AC 43.13-B. I certify this Engine was inspected in reference to Cessna 172 100 hour inspection checklist and has been found to be in an airworthy condition. Engine is approved for RTS at this time. LYCOMING O-320-E2D S/N: L-34839-27A