Probably something really simple such as fuel lines partially clogged,, Mine sat up for 5 yrs when I got my engine and it had some fuel lines issues is all,,, The ethanol in today's fuel causes fuel lines to deteriorate and collapse when fuel is trying to get through,,, only way to check each one for me was to blow threw each and every fuel line until I found the clog...Once zi found which hose was clogged, I just replaced all of the fuel lines inside of engine bay,,,Best to check lines to tank as well to see if they have the newer stable ethanol safe lines installed,,l If not,,, replace those as well,,,
Ranger boats
Perotti pro holders
Avery outdoors superstore