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A dry rotted primer ball with holes in it is a problem plus I would also be worried about the fuel hoses condition too. Inspect everything related to the fuel system carefully. If the hoses leave a black film on your hands or show signs of checking or cracking, feel soft and squishy, or are very brittle, replace them all.
It may be a good idea to cut the primer bulb in half along with a piece of fuel hose and inspect the interior for deterioration. Today's ethanol fuels and moisture can result in phase-separation and if that mixture gets into the fuel system, damage can occur because the alcohol-enriched phase-separated liquid is much more corrosive than plain 10% ethanol (E-10) gasoline.
Be sure to use a Genuine Evinrude primer ball and not an after-market brand.