Let fuel sit in a carb bowl for five days -- very hard start

Your generator has a coincident problem. If the fuel system is all operating correctly,the generator should start within that small time frame.

FWIW, I was the steward of 125 small engines that were seasonally stored for 6 months. In the Spring, all started and ran right except for one series of small Kawasaki engines. It was determined that the fuel-air mixture construction allowed the main jet to clog with oxidized fuel particles. Those Kawasaki engines were treated differently in following years.