We purchased an 18 foot 1994 Starcraft boat with a inboard Merc Cruiser 3.0.We do not have alot of experience with inboards and we had it completely tuned up last week which costs us $600.00. We took it out yesterday and we almost sank! The marine that tuned it up forgot to put the plugs back in and we took on water. Alot...the engine won't start. What should we do?