1980s Wagner micropilot

[polo]

Please help...when setting a course and the autopilot button was pushed the boat would turn slightly to port then auto correct and run straight as a die. However, all of a sudden, when picking a course and hitting autopilot, the rudder turns completely to port and has to be turned off in order to manually steer. Any ideas?

[High Wire]

Guessing bad fluxgate compass. I had one abandoned in place on board from when the AP was upgraded to a Raymarine. It just fell to pieces.

[Lepke]

It could be the compass or magnetic interference. Iron/steel or wiring near the compass.
Parts here: Wagner Micropilot Autopilot Parts and Accessories via Marine-Plus.ComÂ* Merchant
The rebuild Wagner autopilots and parts, maybe have some info.
I have a Wagner service manual, but troubleshooting only covers problems with new installs.

[Marlinmike]

Might want to think about retirement for that old equipment...

[sunchaser]

Originally Posted by polo

Please help...when setting a course and the autopilot button was pushed the boat would turn slightly to port then auto correct and run straight as a die. However, all of a sudden, when picking a course and hitting autopilot, the rudder turns completely to port and has to be turned off in order to manually steer. Any ideas?

It is not uncommon that a re-calibration will fix it. To do this get the manual out and proceed as directed. Usually a windless wide open bay is required as you do several 360s. The button configuration and screen prompts for your specific unit as you do this circling should be in the manual.

I had to do this with my AP20 when it had the symptoms you describe. Yes, remove all metal, tools etc from around the unit's compass.