My l3901 will start and run for a while and then it will just lower the revs and shut down like it’s run out of fuel. I found some trash in the water separator, cleaned it and changed the fuel filter but I still have the same problem.
You need to treat the fuel with algaecide to get rid of the residue, and you also need to treat any storage containers you have. If the algaecide doesn’t work or doesn’t clean the fuel tank, I’d go to the dealer. The fuel system must be under warranty.