I have a 1995 Merc 4.3L with Thunderbolt IV and was wondering how often I should give it it an ignition tune up. This is my first season as the owner and I am not sure when it was done in the past. I feel that the boat could start a little easier and run a little smoother.I saw that they sell kits at West Marine so I am planning on doing this this winter. Also, wondering about the carb and a rebuild. How often should this be done and is it worth it to buy a carb rebuild kit. I am no super mechanic, however, if fairly detailed in a kit I may give it a shot this winter. Any input on kits and level of difficulty please pass on. Thanx