What is the maximum tachometer limit at 4000 feet in the Cessna 152?

In the Cessna 152, the maximum tachometer limit at 4000 feet is set at 2550 RPM. This limit is established to ensure that the engine operates efficiently within its designed parameters, especially when the aircraft is flying at higher elevations where the air density is lower. At 4000 feet, maintaining the engine RPM at 2550 helps to provide adequate power without overworking the engine, reducing the risk of potential mechanical failures and ensuring more reliable performance during flight. Understanding these limits is crucial for pilots to ensure safe operation and compliance with manufacturer specifications.