# Poulan 31cc PB300 gas trimmer, only runs with choke on.



## revalation22_5

First off I am amazed at all the imformation on this site, You guys do a great job.

now for my problem. What I thought was gonna be a general carb cleaning for my father in law has me really scratching my head. He asked me to look at his Poulan Pro PB300 trimmer. Said it would not idle and dies when you try to give it gas. I figured it would be simple and I would just have to clean the carb and maybe replace the diaphgram. so first i cleaned the carb but that did not help so I went to order a carb kit and was told I would have to buy the whole carb no big deal. so i bought the carb and installed it. but it still does not want to run with the coke off. I have replaced
The Fuel Filter
The Fuel Cap (in case it was not venting)
The Carb
The Primer bulb.
I
It will start with the choke on and run and rev up, but when the choke is off it will idle for a few seconds and when you try to give it fuel it will die.

It does not look like the high and low circuts are adjustable because they have a odd cone shaped thing where the screws normally are.

I have also forgot how to route the lines.

Any help would greatly be apprecaited.




















thanks


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## geogrubb

Even though you now have a new carb it can have the same problem as the old one, the carbs are manufactured and the set on the shelf for extended periods of time and the diaphgram and gaskets dry out. Anyway, I think your trimmer has a Walbro WT628 carb and kits are available, as of right now www.oscar-wilson.com has Diaphgram kit D20-WAT for $4.17 with 33 in stock and Repair kit K20-WAT for $8.23 with 48 in stock. If that is not the carb or proper number post back with what is on the trimmer or the new one you purchased and we will try to chase it down. I have seen posts on this forum to make an adjustment tool is drill a 9/64(I think that is the size)hole in the end of a piece of 1/4" dowel stock then tap it over the screws to create a tool for adjustments or removal. For the fuel lines I suggest going to your local Wal-Mart and check the lines on a trimmer, they sell Poulan, that is the surest way to get the lines correct. Have a good one Geo


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## geogrubb

After further checking the 31cc engine may have a Zama Carb and according to the parts list there is no repair kit available for the C1U-W32 carb. However, the C1U-W32 uses repair kit RB-142 and diaphgram/gasket kit GND-78. You can order either at the following.

www.hhlce.com/shop/zama/zama-Index.htm

The RB-142 is $8.95 and the GND-78 is $5.95
Have a good one. Geo


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## revalation22_5

you are correct it is a WT628 carb. I may order a kit for it just to be sure, I really want to get this thing going. Is there anything else it could be?


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## geogrubb

You shouldn't need the whole kit just the diaphgram/gasket kit. Unless you have an air leak somewhere which will create the same symptoms. While you have it running you might spray some carb cleaner along any mateing surfaces(engine housing,carb to crankcase, etc.) to see if the engine tempo changes which would indicate a leak. Have a good one. Geo


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## hec1943

*Exhaust Port Clogged*

I have a Poulan leaf blower and I have found that the exhaust port will begin to build up a carbon deposit after many hours of use. This causes the engine to run slow and somewhat rough. Take the exhaust muffler off and check the port for carbon build-up.

HEC


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## 30yearTech

....


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## geogrubb

Did anyone realize this post is 2 months old without a response from the original poster. Have a good one. Geo


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## 30yearTech

geogrubb said:


> Did anyone realize this post is 2 months old without a response from the original poster. Have a good one. Geo


Ha ha...Apparently not, I know I never paid any attention to the date. 

Have a great one


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## niteman9

I know this thread is over a year old but I am having the same problem. I need to know how to connect the fuel lines. So could someone in the know take his diagram and show how to connect the fuel lines. I am about to run over this thing with my truck.


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## niteman9

Here is the way I have it now and cant seem to get it to start.


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## Lawnmowertech

niteman have you checked the filter ? to make sure it is ok even the purge pump bulb to see if it has a crack in it or air leak ? 

the lines look ok cause you have the fuel coming into the diagphram end of the carb going to the bulb and going back into the tank you can try switching it to see if it works but if it dont work then i would take and look at the other possible causes 

ignition system 

primer system 

etc. 


check the muffler also to see if it is plugged up 

hope this helps 

calvin


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## niteman9

Thank for the reply. The fuel filter, tank, carb, and fuel lines are all new. The primer bulb does not have any cracks. If I cover the shorter fitting and press the bulb does not release until you remove your finger. It seams like this fitting on the bulb is pushing gas when depressed and pulling when released. Is this correct? How do I check the bulb an make sure it is working correctly?

Also with the fuel lines in this position gas runs out the air cleaner side when primer is pushed.


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## Lawnmowertech

niteman9 said:


> Thank for the reply. The fuel filter, tank, carb, and fuel lines are all new. The primer bulb does not have any cracks. If I cover the shorter fitting and press the bulb does not release until you remove your finger. It seams like this fitting on the bulb is pushing gas when depressed and pulling when released. Is this correct? How do I check the bulb an make sure it is working correctly?
> 
> Also with the fuel lines in this position gas runs out the air cleaner side when primer is pushed.


sounds like its working properly 

switch the lines around on the carb see what happens


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## niteman9

I switched the lines on the carb and was able to get it started. Put the string trimmer attachment on it and used it for a while. When I was done I noticed it was on 1/2 choke. When I opened the choke it would die. I pulled it apart again and swapped the lines back on the carb. Couldn't get it started. Swapped them back and got it started again. This time it would run with the choke open. So well see how it works. Thanks for the help.


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## Spit

My experience with Poulan would suggest that you could very likely have problems with your gas lines. The larger diameter hose is the primer line..the smaller line is the fuel line. The fuel line should have the pick-up/filter on one end (inside the gas tank) and the other end goes into the angled inlet on the carb. (I think) 

You can press on the primer and figure which fitting sucks and which one blows...damn that sounds bad!! the blow side should be routed into the tank.
and the other end goes to the other fitting (the straight one) on the carb (I think)

I recently fixed a Craftsman by Poulan and had trouble with the carb until I put a gasket in under the circuit plate. Crazy thing was that there wasn't one there when I opened it up...but the Walbro site's parts breakdown showed one and the kit had it in...so I put it in and it ran great.
Spit


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## grweldon

So,

Are you saying that replacing the fuel filter, fuel lines, primer bulb and carburetor fixed your problem? I have replaces the filter, lines, bulb and diaphram on the carb and I still have the same problem.

Niteman9, could you please verify which of the carb inlet fittings goes to the fuel intake in the gas tank?

Thanks...


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## Deathrite

always two there are... of gaskets in a 2cycle carb. technically one is a spacer... and provides a better material for a good seal.


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## grweldon

Deathrite said:


> always two there are... of gaskets in a 2cycle carb. technically one is a spacer... and provides a better material for a good seal.


I assume we are talking about the diaphram. Let's assume I installed it (them) correctly.


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## Deathrite

if the engine will run even if it is on 1/2 choke then the fuel lines are in the correct order. 
one gasket in the wrong place will normally make it not work at all. if you are getting it to work then yes you put them in correctly. course they might need replacement if you have not done so. if you have then sounds like an air leak. spray carb cleaner around the gaskets (not getting any in the carb inlet) of the engine and see if the engine changes RPM. if so thats where the leak is.


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## Spit

My problem was improved by replacing the gas lines etc. but was not finally resolved until I replaced the small gasket under the circuit plate in the carb.

Spit


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## Deathrite

sounds about right. 7 times out of 10 i target the carb first in problems. its also easy to get to in most 2-cycle.
glad you got it running.


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## JackOfAllTrades

*How to runFuel line's, Poulan Pro Link PPB200*

I have this exact carburetor in my Poulan Pro Link PPB200 Gas Trimmer. The carburetor of course is a Walbro WT628. This Gas Trimmer sat through several seasons without maintenance and the fuel lines rotted on them. Now i need a diagram specifically telling me where I need to hook the fuel lines up from the fuel tank, to the fuel primer bulb assembly, to the carburetor. PLEASE HELP ME!!! Much thanks for any help or input.


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## noesark

Hello folks, I am new to the forum and I am having many of the same issues with the Poulan 250E trimmer. I have replaced the lines, and of course I put them on backwards, but after getting them right, it will crank and run, but when you hit the throttle it dies. I have the bush wacker attachment I need to use and I need full power. It has the Zama carb on it, and I have ordered a kit. Is there any suggestions when I tear into it? The guy at the parts store says the lines have to be the correct outside diameter or they won't seal correctly. Is there some documentation somewhere that gives the diameter of each of the lines? I bought what looked like the correct one, but it may not be.
Noesark


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