Wanted to freshen the runabout motor up. New camshaft, new edelbrock carb and intake, new mallory distributor and coil. Only thing not marine grade is the cam and it is a very mild street cam. The thing runs like a champ on the muffs, but as soon as she is in the water it starts very hard and wont stay running and then it wont restart. Pull it up the ramp hit the key and it fires right off? I am baffled need input