So we now know it's a 5 litre GM V8, supplied by Mercruiser. (I'll edit the title to reflect that)
Have you determined that you have spark? That would be the first thing to do. Yes it ran for 5 minutes, then died. Test for spark. You're looking for a spark that is healthy (strong and blue) that will jump a minimum of 1/2".
As already said, 4 year old fuel isn't fuel enough longer, and no, if it's gone sour it won't run 'like crap', it just won't run, period.
Fuel dripping form the carb.... You need to pull the carb, strip it down and leave it soaking in carb cleaner overnight. Next day, blow it all out, passages included, with compressed air, around 60psi. Then re-assembly following the instruction in the manual. You have the manual, right? (not a seloc or clymer kneepad, the proper Merc factory manual. Probably #15)...
As the fuel was sitting 4 years, I'd also be cleaning out the tank, the line from the tank to the filter, replacing the filter, and stripping and cleaning the fuel pump. ie, ALL of the fuel system. I would do those items while the carb was soaking in the cleaner.
You may find an engine serial number on the cover that was on top of the carb. If not there, a small aluminium tag on the engine block just above the starter motor, starboard side.
Chris.......