[scook]

Again, not an outboard guy, but I would unhook the fuel line at the tank and at the carbs and blow air from the tank end through the whole fuel line/filter system. That way you know that fuel is getting there. Not blowing very hard, so you get as close to an actual conditions test as you can. If the fuel line(s) look crumbly or swollen on the inside, definitely replace all of them. If they’re at all crumbly, a chunk of the line could be in the carb(s) intermittently blocking flow.

With the fuel lines off the carbs, can you squirt some carb cleaner pretty hard in the fuel inlet on each carb? That should have some chance of freeing up a stick float needle and possibly clearing other passages.

If that fails maybe check to see if SpareParts would be willing to rebuild the carbs if you sent them to him?

That’s my best shot at it. There may be some diagnostic YouTube videos that could help, but it really does sound like something in the carburation is plugging up.