I think the real question is how to determine what is really going on. Hands off level at 3500 with 75% power, it turns left at about half a standard rate turn. What are the possible causes? Could the tach be off enough that power exceeds 75%? Rudder trim is at neutral, but could there be a problem there? I understand that flap adjustment can fix it, but I would like to know if I am not fixing the wrong problem. Thanks for the input.