Sorry I am new at all of this still. What do you mean by this one? Isn't the intake the carb itself? What is blowback?
For the exhaust, I looked in there, on the big muffler over on the opposite side where all the exhaust gas shoots out, right? Doesn't look blocked or anything I guess.
As for primer bulb, short tube goes to carb, other tube goes into the engine or someplace. Not sure as I didn't follow it. Bulb looks like it's working as it fills with gas when running and when I push it prior to running I can hear stuff being sucked up into the carb.