Poulan 2000 chain saw WT 20 carb, starts and then shuts off.


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Old 04-20-12, 01:38 PM
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Poulan 2000 chain saw WT 20 carb, starts and then shuts off.

Hello. Recently, I've started working on a chainsaw I had sitting in my shed that hadn't been started in a while. I've replaced the spark plug, fuel line, fuel filter, carb gaskets, and intake gasket and I'm still having trouble getting this thing to run. It starts up but then dies a couple of seconds later. It will only start with the choke completely off. It will not start at on or half-position.

Things I've made sure of:
spark plug is set at about .23
high and low mixtures screws were turned clockwise and backed out at 1 full turn. (I played with these a little bit.)
Fresh fuel/oil mixture
Carburetor was cleaned with carb cleaner. I even took out the inlet needle and sprayed cleaner in it.
Carb gaskets are genuine Walbro and fit like they are suppose to. (Not sure about intake gasket.)

I saw a thread similar to this on already posted on this forum and read through it but couldn't find anything that could pinpoint the problem. If anyone has any other thoughts, I'd greatly appreciate hearing them. Lastly, here is a pic of the carb:

 
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Old 04-20-12, 05:02 PM
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Sounds like the fuel pump in it isn't pumping any fuel into the carb. It could have a problem with the diaphragm needle that shuts things off in the reservoir, but most likely the fuel isn't getting into the carb.

I take it you put a complete kit in the carb to include the diaphragm? Providing everything went back together OK, you could have a leak in one of the fuel lines so the pump can't draw. Or the filter may not be under fuel in the tank. Or the pulse port coming from the crank case to the carb could be plugged or blocked off with the wrong gasket.

Depending how enthusiastic you are with this you might try checking the lines again for fit and routing: Then if nothing try:

Dumping all but 1/2 of the gas out of the tank, wipe the tank top really well, then put a piece of plastic with a hole in it over the tank opening. Hold the plastic on tight with a rubber band and pressurize the tank either by blowing into the tank or using compressed air with about 5 lbs of pressure for about three or four seconds.

Then, with no choke and half throttle see if it will start and run longer. If it does and dies after about thirty seconds, the diaphragm isn't pumping.

Since it starts with no choke, I get the feeling something isn't doing its job in the gas sealing department, though. But check it out and post back.
 
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Old 04-20-12, 08:36 PM
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If it only starts with no choke, I have to assume it is getting too much gas. If so, something is wrong in the carb. Did you get the spring in place under the inlet metering needle tab?
 
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Old 04-22-12, 06:24 AM
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Here's the proper link to the pic (I hope). Seems it got blocked when I originally posted.
http://goo.gl/MmMm7

marbobj: I will check this out as soon as I can get to it. I did not replace the needle. Just the gaskets.

cheese: The spring is in place. I tapped the little lever. The needle raises up and down as it should.
 
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Old 04-22-12, 07:34 AM
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You may just have a flooded condition. That can cloud everything. For instance you may flood the engine when it doesn't start right off. That brings you to the choke off to get it started. Then it tries to start but only runs for a short time because the flooding of the crank hasn't cleared out.

All in all you may everything working right, but the engine just hasn't had the first start from having sit so long. Once it gets started and runs a little to clear it out it may work fine for you.

Usually for a first start like that, when it's giving you headaches, if you dump all the gas out of the tank, then full choke, spin it over a dozen times to clear all the fuel out of it. Then pull the plug, spin it a few more times to clear the combustion chamber. Add a little fuel mix directly into the spark plug hole and with a new plug, no choke, half throttle see if it will fire and try to run. Repeat, then add gas back to the tank.

Doing this clears it out for the first run. After that it may be more cooperative for you.
 
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Old 04-22-12, 11:05 AM
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Are you trying to start it with the throttle wide open? If not, do so.
 
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Old 04-22-12, 06:27 PM
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CHEESE: I have always tried starting it at full throttle.

I will look into your guys' suggestions tomorrow after work. Thanks for the tips.
 
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Old 05-10-12, 12:24 PM
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I've tried replacing the inlet needle and the screen. Changed gaskets again and tried another fuel filter. Still doing the same thing though. I am completely stumped.
 
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Old 05-10-12, 05:52 PM
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I managed to get it to run for about a minute before it died today. After it stopped running, I noticed that on the bag sitting a few inches from the muffler, there was an oily residue on it, apparently spit out from the muffler. Here is a photo: http://goo.gl/TyQsh

What do you think? Too much gas? I've only got the mixture screws out 1 full turn.
 
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Old 05-10-12, 06:12 PM
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You may just have a bad carburetor. The ethanol in todays gas eats the sealant from around the welch plugs in the carb and cause lots of problems. It sounds like it is still flooding.
 
 

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