Raymarine C80 with autopilot
A year after owning my Hunter 386, I experienced the same problems. Try the recommendations made above, including the location of the fluxgate compass. Ensure it's located in the lowest part of the boat (ours in under the aft berth mattress on a bulkhead with nothing metal around it).Accommplish a reswinging of the compass, per the book under calm conditions. Also, might try turning the system totally off, resetting the power breaker down below, waiting 30 seconds and reboot the entire system. Sometimes that works.I've had to reset/repower my unit occasionally and it resets OK. However, the first year of owning the boat, I had the local Raymarine folks out to the boat to fix this recurring problem. They couldn't fix it in their shop so they sent it back to Raymarine who ended up sending me a completely new system replacement. It works better now, but if I lose the GPS signal it's apt to confuse the autopilot and the system goes bonkers, until I reset/repower the entire system.