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poulan 2700 chain saw/ fuel line


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04-26-10, 08:44 PM   #1  
poulan 2700 chain saw/ fuel line

i have an older (15-20/year old) poulan chain saw, (it was my dad's,has not run in 12 years) with a walboro carb, that has the crankcase pulse for the fuel pump located on top of the carb. by way of a fuel line tube.

where does the line attatch to the crankcase?
all the lines have crumbled off!
is it possible that the pulse signal is created in the fuel tank?

would like any help.
thanks-mike

 
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newtofta's Avatar
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04-27-10, 09:18 AM   #2  
i found my answer at another forum.
thanks
mike

 
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04-27-10, 10:06 AM   #3  
I'm not an Xpert on this kind of equipment.

But my limited understanding is that diaphragm carburetors common in this kind of equipment have their own fuel pumps as a part of the carburetor itself, using differential pressures generated by the operation of the carburetor to pump fuel regardless of the position of the engine or fuel tank.

By the "crankcase pulse," are you talking about the plastic primer bulb?

 
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04-27-10, 05:39 PM   #4  
yes,the diaphram carbs have thier own built in fuel pump.
the pump diaphram is pulsed (up & down) by the pressure pulse in the crankcase created as the piston moves up & down in a sealed crankcase.
I am no 'EXPERT' either but i understand how they work.

after i found that the tube connects to a nipple on the crankcase-& routed the lines.
in will start ,but not stay running.
I found that the seal under the flywheel had popped out! this creating a 'NON' sealed crankcase.
i am now looking for a new seal.

 
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04-27-10, 06:02 PM   #5  
I'd have to say you are pretty good to have identified what sounds like a pretty obscure problem to me!

 
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