Raymarine EV series autopilot diagnostics

Raymarine EV autopilots (Evolution series) rely on the EV-1 or EV-2 core computer (a 9-axis motion sensor + processor). Setup: the EV core must be mounted level, on the boat's centerline, with connectors facing forward. Bad mounting = bad heading, no exceptions. Rudder feedback (analog voltage from the rudder position sensor) is required for reliable steering, most "hunt" and "overshoot" complaints trace to a bad rudder feedback signal. Test: with autopilot in standby, rotate the wheel manually and watch the rudder angle display track smoothly across the full range. Dockside calibration must be run once after installation: rudder limits, heading alignment, and a 360-degree compass swing at 3-4 knots in open water. Common failures: (1) Compass drift, usually magnetic interference from a nearby speaker or engine, move the EV core. (2) Loss of NMEA 2000 data, check backbone terminators (see NMEA 2000 rules). (3) Drive clutch not engaging, pump/ram wiring or failed clutch coil. (4) Erratic behavior in slow-speed maneuvers, increase Response setting.