Expert: Marc Mielhausen - 10/15/2004

Question
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Followup To
Question -
I have a poulan chain saw, I think a 3.3cu inch engine disp. Basically I can get it to start, it runs for 5 sec then dies. I paid a shop 25 bucks for an estimate of 100 bucks to rebuild the carb. Crazy. I can buy the same saw new for 140.00!
I work on engines occasionally so I dont mind tearing into stuff. I ran gas treated with stabil last time I used the saw. I did spray carb cleaner in the throat of the carb.didnt help.
Kevin
Answer -
Try loosening off the fuel cap slightly before you start it.  Quite often, the tank vent gets plugged with sawdust and when the tank doesn't vent correctly, the engine starts and then dies.  If this helps, locate the tank vent and clean or replace as required.  If there is no change, you might want to try adjusting both of the mixtures to 1 1/2 turns out from lightly seated.  Then try to adjust from there.  If this has no effect, the carb will need some attention.  Also check the fuel filter and impulse hose from the crankcase, if equipped, while you are rebuilding the carb.  Hope this helps.
Ok I will try the fuel cap. I actually have already diagnosed the fuel filter as being bad for a previous problem. (would not start) So currently I am running it without a fuel filter until I fix the stalling problem. I have also adjusted the carb settings per the manual but that has not helped. So I will try the fuel cap and get back to you. Not sure what the impulse hose is but I will look for it. Thanks,
Kevin

Answer
Your saw may or may not have an impulse hose.  The carb needs to use crankcase pulses to actuate the fuel pump diaphram in the carb.  These pulses either come through a hose to the carb or a small hole through the intake spacer to the carb body.  If it's a hose, I'd check it.  If it's a hole, make sure the passage is clear.