Here is what
Wikipedia has to say about it:
An unusual feature of the 175 is the geared
Continental GO-300 engine. Whereas most single-engine airplanes use direct drive, this engine drives the propeller through a reducing
gearbox, so the engine runs at 3200 rpm to turn the propeller at 2400 rpm (4:3). The GO-300 engine suffered reliability problems and helped give the 175 a poor reputation. Some Skylarks flying today have been converted to larger-displacement direct-drive engines
[3][4] though almost 90% still retain the GO-300.
[5]
The GO-300's tainted reputation was largely undeserved, since its problems were the result of pilots who were unfamiliar with gear reduction engines, simply not operating the engine at the higher RPMs specified in the C-175 Pilot's Operating Handbook. Pilots unfamiliar with the engine often operated the engine at the low RPM settings (2300-2700) appropriate to direct-drive engines, while the 175's Operating Handbook called for cruising at 2900 RPM. The low RPM caused harmonic vibration in the reduction gear between the
quill shaft (that turned the propeller) and crankshaft, and the low power resulted in low airspeeds that prevented the engine's air-cooling system from operating effectively, resulting in chronic reliability problems for engines not operated at the recommended power settings.
Ian BB