Stihl BR550 fuel tank vent

[Carls421]

Hi again,
So on the bench I have a BR550 backpack blower, it’s had a few issues which I’ve fixed but this one particular thing I’m struggling with and could do with a bit of advice...
I had to replace the primer bulb as it was split, i know I've put the pipes back on the right way but it’s not filling the bulb? The tank did have a slight hole in it but I’ve fixed that, but my question is about the fuel tank vent, which direction should it vent? Without wanting to sound daft, am i right in saying that the “vent” should suck air in and not blow out? I block all holes up and put slight pressure into the tank but air blows out of the vent? It should pressurise that tank when you pump the bulb right?

 

[Carls421]

Just a few more things to add, when i try to blow down the pipe which should be delivering fuel to the carb (blowing towards the carb) I can’t hear anything, ie feels blocked. Is that right? Or would the fuel go up that pipe once it’s being turned over?

Also, when I suck the pipe that should be sucking the fuel up to the primer (purge) bulb I can only suck air, no fuel comes up even though the tank is full and it’s a new fuel pipe

 

[Rosko420]

The primer pulls the fuel through the carb and returns through the primer.pull off line from carb to tank and see if you can draw fuel.sounds like you might be thinking the primer works differently