Re: 1975 75 horse evinrude
Curious as to how you know that fuel is going to all the carburetors but not filling up the carburetor bowls? You might have a blockage somewhere so let's start from the fuel source and see where it is. Assuming you have had this motor awhile, you know how to start it when it is cold, and the problem just began since you said it ran last week.
Make sure the vent on the tank is open. Try removing the big screw on the fuel pump and check the filter screen for a blockage. Before you put the fuel pump back together again, give the bulb a squeeze and see if fuel comes out. If all is well, put the fuel pump back together. If you can, try to remove one of the fuel lines that leads attaches to a carburetor. Give the bulb another squeeze and see if you get fuel coming out. Do it for all the carburetors, if you can easily remove the fuel hose that leads to them. If you notice any pieces of stuff besides fuel during these tests, you likely have degraded fuel lines due to ethanol. That stuff is likely in your carburetor and a rebuild is in order. Also replace the fuel lines during the rebuild process.