1990 mercury 40 (4cyl) 2 stroke

[goose slayer]

motor has been running fine all year and I’ve been doing lots of trolling. Last trip out at full speed I lost power. 26mph down to 8 like I was dragging something, then it stalled. Hard to restart and the primer ball was going soft. Finally got it started but had to keep choking it. Then it ran fine back to the dock. Changed primer ball and took another trip. This time hard starting and didn’t want to stay running at troll speed but ran fine at throttle Came home pulled plugs. See attached pic. What’s everyone’s thought from the pic. Just got 4 new plugs and a new fuel/water separator but haven’t had a chance to take it for a test run