Carb primer bulb air lock/pressure building

[CFOD]

Hi, I've just tried to give my Husqvarna carb a spruce up, but when I try and prime the saw there is pressure building in the 3 fuel pipes, and no fuel circulating. Also have huge pressure in the tank too. Any ideas?

 

[RED-85-Z51]

Lines not routed right

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[CFOD]

Lines not routed right

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Apparently they are according to a few videos, such as this

 

[buzz sawyer]

Did you change any parts in the carb? Maybe wrong gasket somewhere?

 

[CFOD]

Did you change any parts in the carb? Maybe wrong gasket somewhere?

This is what I assumed it was. I went back into the carb and replaced all the gaskets as the diagram on the Zama website shows. I'm thinking maybe I ordered the wrong gasket set, so have reordered another one, OR it could be a blockage within the carb somewhere? but with no access to an air compressor I don't know how to clear it (should that be what it is)

 

[sean donato]

Just a dumb question but are you sure you didnt swap the fuel lines on the back of the primer? Did that once..... felt like an idiot.

 

[CFOD]

Just a dumb question but are you sure you didnt swap the fuel lines on the back of the primer? Did that once..... felt like an idiot.

To begin with, yes. However swapping them to their correct positions has not fixed the issue

 

[CFOD]

Here's some pictures to show the current situation. This was the best I could get, very little fuel in the system, filled with air bubbles and a lot of pressure

Edit: Obviously I've cleaned the saw since this initial pic, no way am I letting all that crap getting into the cylinder/carb

 

[brad ruch]

You replace the primer bulb?lines don't look like they been replaced.

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[sean donato]

I assume those are pre carb rebuild pictures? If so I'd also assume something is wonky in the carb, only thing that gets me is pressure building in the tank. You should be able to on the primer till you blue in the face and just circulate fuel through the carb back to tank. I'd definitely pop the carb apart again. Makes sure you didnt get the gaskets flipped or bait of dirt in somewhere it doesnt belong. Carb cleaner can be used to check the passages. Just be careful you dont spray yourself with it...

 

[CFOD]

You replace the primer bulb?lines don't look like they been replaced.

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Havent replaced bulb or lines, new ones on the way. Think that'll do it?

 

[CFOD]

I assume those are pre carb rebuild pictures? If so I'd also assume something is wonky in the carb, only thing that gets me is pressure building in the tank. You should be able to on the primer till you blue in the face and just circulate fuel through the carb back to tank. I'd definitely pop the carb apart again. Makes sure you didnt get the gaskets flipped or bait of dirt in somewhere it doesnt belong. Carb cleaner can be used to check the passages. Just be careful you dont spray yourself with it...

No fuel is entering the fuel pipes at all, its purely air, after 6 it 7 pushes of the bulb it feels like its rock solid under pressure. Must be a carb issue, christ knows what I've done.
Seems to be a common theme when working on my saws that everything isn't too difficult until the carb gets involved

 

[brad ruch]

Could be a bad primer bulb.ones I've had go bad wouldn't hardly pull fuel threw.otherwise there something with the carb wrong.

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[brad ruch]

What model saw?

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[CFOD]

What model saw?

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Husky 235 X-Torq

 

[sean donato]

Check your fuel line from tank to primer as well. I'm thinking it has a hole in it in the tank above the fuel level, possibly. At any rate it's a good idea to replace the lines when you do a carb overhaul... or at least check them out and replace the clunk in the tank.

 

[CFOD]

Check your fuel line from tank to primer as well. I'm thinking it has a hole in it in the tank above the fuel level, possibly. At any rate it's a good idea to replace the lines when you do a carb overhaul... or at least check them out and replace the clunk in the tank.

Oh that's interesting. I cant find specific fuel lines so I've ordered generic fuel hose with the same dimensions as was essentially gonna cut my own. Should there be a hole in the hose, in the tank? Also mind explaining what a clunk is?

 

[sean donato]

No no holes in the fuel line save where it goes on the clunk(fuel filter) and carb. I was thinking it may have gotten a tear or hole in it from moving the it around to unhook it. Husqy needs that stupid black rubber line so the clunk will swing around proper in the tank, And fit tight in the tank hole. The Tygon stuff doesnt seem to work right. At least I've never had luck with it. I did just get some stihl line I'm going to try out next time I redo a saw fuel system. Post up how your line fits then, and what size you bought... I'd like to know for future reference

 

[atpchas]

I'd start by disconnecting lines from primer mechanism, pop the primer out, then attach some hoses to the primer nipples and see if the primer will move fuel - stick suction hose in a small container of mix with return line going back to container. That should let you know if the primer is innocent or guilty.

 

[grizz55chev]

I'd start by disconnecting lines from primer mechanism, pop the primer out, then attach some hoses to the primer nipples and see if the primer will move fuel - stick suction hose in a small container of mix with return line going back to container. That should let you know if the primer is innocent or guilty.

Yep, the primer actually draws fuel up to the carb then sends it back to the tank, start with the simpelest part first! the short nipple on the bulb is the suction side.