i inheareted a 1984 seasprite with a 120 merc. lots of rotted wood so im restoring the boat in the memory of my cousin that owned it. when he had it the motor would start on dry land but take to the lake and it just turned over and would not start. pulled it from the water and went home ,tryed starting in the driveway and it fired right up poor guy did this trip 3 times before he gave up and decided to refinish the serface then he would work on the motor problem. my question is what would make it not start in the water but start on dry land this my first boat and i have no clues thanks in advance