1995 Bayliner Capri 1850 LS with a Mercruiser 3.0 LX Digital Electronic Ignition System

Problem: Engine starts, will not stay running.

Two weeks ago, I hooked the muffs up to make sure the boat was ready to fire before putting it in the river. It fired right up, and sounded like it was idling a little lower than normal (seemed to have a bit of a high idle before.) After about 1 minute, it died. It would continue to start, but would not run more than a few seconds. I have researched hours and hours, and piddled around on it for days. I've gotten to the point I'm over it. I have cleaned the filter going into the carb (it was very gunked up with what I was told is probably water from my description of it). I replaced the fuel filter inside the pump. I replaced the filter on the fuel/ water separator, and hooked it up (previous owner disconnected it for some reason.) I checked the anti-siphon valve and it seemed to be proper. I unhooked the fuel line going into the carb, placed a coffee can around it, and cranked the engine, and fuel shot out. I have put in a can of Lucas Complete Engine Treatment in the fuel tank, dry gas, and used seafoam spray on the carb. I replaced the carb base gasket as well, thinking I saw a vacuum leak there and looking wet. I also replaced the plug wires, and cap, due to a wire just resting on the cap and becoming very rusted, and the cap being corroded on that plug. I have 12 volts on all of the locations of my purple wire. I tried to adjust the idle speed, and mixture screws on the carburetor, with little luck. The only way I've been able to keep it running longer than a few seconds, is by holding the choke plate nearly shut. Please help before I junk this boat. A part of me wants to change the coil, but hate to let this thing nickel and dime me to death, it is not a cheap part.