Only starts/runs when Air Intake blocked.

chuckgtt

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POULAN PRO - 2014, 38" RIDING MOWER, PB145G38, ENGINE B&S MODEL NO 31R607-0005-G1 (585822301) 14.5HP, 499cc 1-cyl gasoline: Will not start at any position on the throttle. Will start if I cover the air intake with my fingers, runs with the air that slips past my fingers, if I spread my fingers any it dies, does not smoke or smell rich. outside air temp 80, humidity 28%, half tank of gas. Had trouble last week, started on full choke, after warm up ran at the normal throttle level. Did annual clean and adjust in January, change oil (synthetic), new plug, exterior cleaned, tank/lines/carb flushed, new fuel filter, new air filter, adjusted coil. Have been mowing since February. Any suggestion?
 

Born2Mow

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Did you leave Ethanol gasoline in the carb over the winter ? If so, you'll need to rebuild your carb, paying special attention to the low speed fuel passages and jets.

You and about 200 of your closest friends all did the same thing.
 

chuckgtt

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I mow all year in this part of Texas. In January I always clean the tank, lines, and carb with a product designed to remove residuals. I have mowed 7 times (2 aces each time) since then. We are up to weekly mowing now and I used the mower for at least 7 hours since the cleaning to haul limbs and yard waste. That's a lot of gas through that carb. The gas is rarely over 10 days old, I use stabilizer in the can. In trimmers, blowers, tillers and other equipment that sit, I use only Ethanol free fuels. Never had an Ethanol issue in last 6 years I've owned this mower, but I will check that to be sure. More than likely I will replace the carb as the rebuild kit has minimal user replaceable parts and my eye sight and manual dexterity is not what it use to be. I suspect this is a carb issue, but I am getting old and want other opinions to save me time and discomfort hunched over a lawn mower. Any other suggestions? Thank You
 

bertsmobile1

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The engine is not getting enough fuel
So either fuel is not getting to the carb, going through the carb or there is an air leak between the carb & the engine.
Thus you start by confirming the fuel supply to the carb by pulling off the fuel line & cranking the engine .
Then you hook it back up, remove the float bowl ( checking for water or dirt ) and crank the engine again working the float with your finger to check that fuel flows freely and cuts off before the float runs out of travel.
Next you check the fuel solenoid is retracting all the way, debris builds up under the plunger and needs to be cleaned out periodically .
If that is all good remove the carb & clean the fuel passageways.
When you have finished refit the float bowl , fuel line & solenoid.
Turn on the ignition to activate the solenoid then turn the carb sideways and blow low pressure air through the carb.
You should see & feel fuel damp air coming out the other side.
Refit and see how it goes.
 
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