What is the lower chamber check valve in a Showa PTT system also referred to as?

In a Showa PTT (Power Tilt and Trim) system, the lower chamber check valve is commonly referred to as the up main valve. This component plays a crucial role in controlling the hydraulic fluid flow, particularly when the system is tilting or trimming upwards. It allows fluid to move from the lower chamber to the upper chamber, enabling the outboard motor or other surfaces to rise.

Identifying the lower chamber check valve as the up main valve highlights its functionality in the hydraulic system, where it primarily facilitates upward motion by regulating the pressurized fluid. Proper understanding of this terminology is important for technicians when diagnosing or repairing tilt and trim systems, as it helps in recognizing the specific functions of various valves and components involved. Each of the other choices refers to different valves or functions within hydraulic systems; for example, the down main valve pertains to fluid flow regulation when tilting down, the relief valve is designed to release excess pressure, and the pressure regulator focuses on maintaining a constant pressure in the system.