Carb not pulling fuel

Ace Smith

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I've searched the forums, but can't find this issue in any old posts....
I have a Poulan mower with a 17.5 hp B&S engine. This is a gravity-feed fuel system.
This spring I found fire ants in my air filter housing. I cleaned them out, and replaced the filter. Since then, the carb is not pulling fuel like it should. The mower will run awhile, then quit. When I check the fuel filter, it is almost dry. Letting the mower sit for awhile, the fuel lines will fill back up, and the mower will run awhile again. It was suggested that maybe some of the ants got into the carb. (I didn't think ants liked gas!) I removed the fuel intake line and used an air hose to blow out the carb. No help. The mower still runs about 20 min, then quits, until I give it time to refill the fuel line.
I have replaced the fuel filter, and verified that fuel is running freely from the tank when I disconnect the line at the carb.
I'm assuming that the ants were what caused this problem, since I never had this issue before. Any ideas on what else might be the issue, or what else I can do to diagnose it?
 

ILENGINE

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It is not unusual for the fuel filter to look almost empty. If you have good fuel flow at the carb, that eliminated that part of the system. Does the mower sputter and die like running out of gas, or just die like turn off the key.
 

Ace Smith

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It is not unusual for the fuel filter to look almost empty. If you have good fuel flow at the carb, that eliminated that part of the system. Does the mower sputter and die like running out of gas, or just die like turn off the key.

It sputters from no gas. Normally, the fuel filter is full of fuel, easily seen. When the mower dies, the filter is empty. Allowing it to sit for an hour refills it, and the mower runs again. Or, I can disconnect the fuel line at the carb, and the line will refill with gas. It's almost like a vacuum is forming in the line, preventing fuel from flowing.
 

ILENGINE

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Which fuel filter ar you using. Mowers since 2012 have run a closed fuel system, that causes the tank to run under a slight vacuum. I have run into cases where the fuel filter will be too restrictive and cause your symptoms, but that same filter will work fine in the older vented fuel systems.
 

Tinkerer200

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Maybe I missed this but have you checked for good flow from the fuel line when disconnecting at the carb? I suspect debris locking the fuel out let in the tank OR wrong fuel filter as said above.

Walt Conner
 
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