Raymarine Double Pilot Check Valve, For Autopilot Systems

Overview

The Raymarine M81166 is a double pilot check valve for marine hydraulic steering systems using a Raymarine autopilot pump. It helps hold hydraulic pressure in the steering circuit and limits unwanted hydraulic movement, including helm movement while the autopilot pump is operating.

This valve is a practical service part for boats with hydraulic steering where the autopilot needs controlled flow through the circuit. It is especially relevant when steering response feels inconsistent, the wheel moves during autopilot operation, or the installation layout requires a double pilot check valve as part of the hydraulic plumbing.

Key features

• Double pilot check valve for marine hydraulic autopilot steering installations.
• Helps prevent backflow and pressure loss in the hydraulic steering circuit.
• Helps keep the helm from turning when an electric hydraulic autopilot pump is running.
• Suitable as a replacement part for Raymarine autopilot systems that use this valve type.
• Supports steadier autopilot steering control by reducing unwanted movement in the hydraulic circuit.

Installation and setup

Install this valve in the hydraulic steering circuit where the autopilot plumbing layout calls for a double pilot check valve. Because it works inside a pressurized steering system, the hydraulic lines should be routed, tightened, filled, and bled carefully so the autopilot pump and helm can operate without trapped air or fluid leaks.

Before ordering, confirm that the vessel uses a Raymarine hydraulic autopilot arrangement that requires this valve style. Matching the valve to the steering layout matters more than the boat type, so check the existing installation, hydraulic pump setup, and service documentation for the system on board.

Use cases on board

This part is a good match for powerboats and sailboats with hydraulic steering where a Raymarine autopilot controls an electric hydraulic pump. It is most useful in steering systems where hydraulic flow must be held in check so the autopilot can maintain course without unwanted movement through the helm circuit.

Maintenance and care

As with any hydraulic steering component, inspect the surrounding fittings and hose connections during routine service. Look for leaks, corrosion around fittings, low fluid level, or steering behavior that changes under autopilot load, since those signs can point to hydraulic circuit issues that should be corrected before extended cruising or offshore use.