P3314 fuel issues

Dog1234

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I have a used Poulan P3314 chain saw. My friend left gas in carb and it destroyed the fuel lines and purging bulb. So he changed lines and bulb and the unit won't start. So, I took the task of repairing it. I got a K-20 carb kit and installed it. O yea its a (Walbro WTA30,812 carb on this unit). After the kit was installed I noticed heavy fuel in the piston area, at times had fuel coming out the carb. Man just confusing. So I tried the bulb alone and fuel flowed as it should. I thought the fuel lines may be crossed on the carb. I swopped them and not deal. So I took carb off and attached the fuel line system to the carb and pumped the bulb with the line attached to the carb one way the bulb would go in and basically not come out? I swopped the line on the carb and the bulb would pump in and out as normal but just air no fuel.

I have take the carb apart several times to make sure it was assembled correctly. It appears to be...…….... I have had a had time locating exact directions on how to do the kit install. It appears the fuel wont flow through the carb as it is intended to. As I said the carb is off the unit and all lines and bulb are attached. I inserted the suction line in fuel and the bulb goes in and does not come out. I swopped the fuel line position on the carb and pumped again, the bulb goes in and out as it should but just moves air. The bulb alone works perfect, just on the carb is where the issue is.

Thanks in advance
 

bertsmobile1

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Firstly Walbro have service manuals and videos all readily available on line
http://www.walbro.com/parts-services/
You just have to make the effort to scroll to the bottom left corner of the screen for the links.

Next all cube carbs work the same, there are only 2 kinds rotary valve & butterfly so if your EXACT CARB is not mentioned right down to the last digit, it does not matter they all WORK THE SAME.

Next you really have to clean them out properly and that requires more than a soak in simple green overnight a a few blasts of carb cleaner.
On the subject of carb cleaner, most of them destroy the seals in cube carbs which s why Walbro floggs their own formula.
Then cube carbs are really really really really really really really hard to clean if they are full of stale fuel tars & varnishes.
Some have needed better than 20 hours of ultrasound in solvent to finally clear them.

Next the primer is actually a PURGE valve and it sucks the air first then the fuel OUT of the carb and returns into the fuel tank.
The carb has 2 to 4 one way valves in it and the purge VALVE also has a one way valve in it, thus it only works one way.
Hook it up so it sucks against a valve that closes under vacuum will not work so the bulb rill not return , even if the valve in it is clean & working properly.
Back a few days ago Boo posted a link called Carb info or some thing like that.
It goes to a Pommie web site with the most boring presenter ever on the web but if you can stay awake through a couple of his 1 hour long presentations you will have all the knowledge needed to tackle the job with confidence & understanding.
Sorry, no gen X,Y,Z instant 10 second fix.
 

Dog1234

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I understand the one way valves. I also understand the way the purge bulb is superposed to work. I have spend hours on this darn thing and now it just a matter of I will figure it out or dye trying LOL!!!!!!!!!

Been at it again tonight. Here is where I am at now. O yea also FULLY understand the routing of the fuel lines. With fuel line from tank (small with filter) going to carb on throttle side then on choke side that line is going to purge bulb, then from purge bulb to tank return. With this set up the bulb does nothing. As I push it in it just come right back out and basically I only hear a little air swishing back and forth. Almost like their is air getting into the system somewhere. So I took carb apart again, inspected all gaskets, seals etc to try to find where air may be getting into the system (no luck) I reversed the lines on the bulb in it pushed gas into the carb backwards (in through the out door) and the fuel was going out the butterfly valve on front of carb. So i took off the lines on the bulb and put my finger on one nipple and pressed the bulb. The bulb went in and out and seemed to get soft as I think it should????? Then on the other nipple I think it should be hard and not let any air in or out, well it depresses freely and air swishes in and out. It is a new bulb, could this be my problem or am I just barking up the wrong tree?
 

bertsmobile1

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And this is why I directed you to the service manuals.
The purge bulb has single or double duck bill valve.
The valve allows fluids to pass in one direction only and in the case of a purge valve the air comes out past the valve then can not get in.
This forces air ( or fuel ) to come in the other side of the purge valve.
Now the purge valve can be either part of the carb or remote.
When part of the carb the ( suck ) side draws fuel from the metering chamber , into the bulb then back into the fuel tank
Actually I really can't be bothered going through all of this.
So the answer you are looking for is in this video which is one of the ones that Boo's post that you could not be bothered looking for directed people to.

https://www.youtube.com/watch?v=jalfpoldyo0

Got to be the most boring presentation ever but has all the information you need to work out what is going on with your carb.
 
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