Re: 1977 merc 188hp fuel issue
Have you tried filling the float bowl with fuel, or running on starting fluid to allow it time to pump fuel? There is a lot of apparatus for the gas to be pumped through before it reaches the carb. Its been sitting for 7 years, the lines are surely dry, if not needing replacement anyways. When I saved mine from the grave it took maybe 10 seconds of running on spray before gas reached the carb.
Either way a stuck float will not typically cause an engine to get no fuel. It will do quite the opposite actually
But for when you do get it pumping, if it has the holley carb, you can check float level by removing the sight plug at the side of the bowl. Gas should just start to trickle out with engine running. Clockwise lowers the float level and counter clockwise will raise the level on the screw at the top of the float bowl.
Anyways try what I said first. For all you know right now the engine doesnt run anyways. I'd be on the starting fluid in a heartbeat. If fuel still doesnt pump, replace all the lines, and the pump. Its old and could use it anyway. Cheap insurance. End of story.