Working on a 2000 gti for a friend it was runing fine they came to the shore shut it down about 20 min later went to leave and it would not run. Out of water it will start but will only rev up and then go dead after a couple seconds it will not idle. I have not looked at this ski but he said the spark is weak looking and comes and goes, I am leaning more to a gas problem but looking for suggestions> Thanks