Carburetor Piston Wear

     Mine looked the same as that on my 912uls after 2000 hours. I did a complete overhaul on them, and they have been working flawlessly for 35 hours now. Not sure what they ran like before as I purchased the engine no longer in the flight school aircraft.

     When I inspected the gearbox, everything was totally worn out including the prop shaft splines, even though the logs stated a gearbox overhaul 500 hours prior. Which made me believe the previous owner probably wasn't great at maintaining carb syncs etc. and potentially being part cause for the wear on the carb slides.

Check piston top slide for wear, also check top chamber for wear (ie. where piston slides into top chamber)

Replace if necessary.    Gearbox friction torque, syncing carbs, and dynamic balancing prop are all important factors.   Don't forget to check engine mount rubber condition.

Thank you for all your help and input. I went ahead and replaced the necessary carburetor parts, and the gearbox is coming off soon for inspection. Cheers.