I have a 2007 - 290 SeaRay Sundancer cabin cruiser. The motors are (2) 4.3L Mercruisers w/Bravo III SS dual props. I decided to change the plugs on both engines for the boat has been sluggish when getting on plane. I have never changed plugs on a marine motor before and realized that the radiator hoses in the front of the engines had to be removed in order to replace 1,2 & 3 plugs. In doing this some of the anti-freeze was loss during this process. Upon completing installing all (12) plugs I re-filled both radiator tanks and cranked up the motors. My port side engine started running hot - 190 degress, so I shut it off. The starboard engine ran fine @ the normal 165-170 degree range. Is it possible for air to get into the system where the antifreeze solution will not circulate? If so, what is the easiest way in getting any air in the system out. Never had any any issues with the motors running hot until now.