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briggs problem


bud119195

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does anyone know what would cause my 8 hp briggs to sheer the flywheel key?The motor will start and run a few seconds and shut off. Check motor and have no spark . Its done this 3 times and found flywheel key sheered and am getting sick of pulling it apart to fix it.
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first off: it's a vertical engine correct? look at this first: is the nut torqued properly? is there play on the shaft / flywheel? using the correct key? is there a fin on the flywheel busted off? any weird vibrations? dose it run smooth when running? is the crank shaft straight. with out the flywheel on spin the engine and look for out of round, and wobble. "look over the key way on both fly & crank for any ware". this will help us help you. if there is anything I have not asked that you have noticed please tell. thanks
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Are you using a Part Numbered OEM key or a generic equivalent. Some generics are too soft to hold up to that application.
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I have a pack of arnold brand keys. I'll get some briggs and try them.The motor was fine untill I had the tractor tilted side ways for a couple days soaking a rusted wheel.and I tipped it down and had alot of gas in motor and had a problem since.
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If you are shearing the keys, then the nut is not being torqued tight enough. The taper of the shaft and the flywheel, when mated with the correct torque on the nut will transmit the necessary torque. The key is only used to align the flywheel properly, and should not be relied on to transmit torque. I have seen Pro Stock garden tractor pullers run their engines without keys. The this so they can index the flywheel wherever they want to change timing. They just have to make sure of the torque on the flywheel nut.
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