I have a problem with the overheat alarm. It only happens at low rpm in a trailing sea. The pisser tube is not flowing hard like it should so I replaced the water pump impeller but it made no difference and the impeller looked fine. I am Thinking that the theromostat might need replacing. What else would make the flow not hard. I am planning on doing this myself but need some advice. First , where can I get a service manual for a F225 because I would not know where to start looking for a thermostat? Second, any other ideas? Thanks