12 hp Briggs


Old 05-30-13, 06:41 AM
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12 hp Briggs

Engine sheared flywheel key. Replaced key, torqued flywheel. Engine runs, but it sounds like it is out of time, muffler & exhaust pipe glow red in a few minutes. engine working very hard. What is wrong. Mower & tractor worked fine before.
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Old 05-30-13, 06:45 AM
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I would go back to the flywheel and double check the key.
Old 05-30-13, 09:11 AM
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I am curious how you sheared the flywheel key on a lawn tractor? I've seen it many times on push mowers when you hit something with the blade but on other engines I've only seen it, usually on souped up or poorly adjusted engines when it backfires.
Old 05-30-13, 06:34 PM
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I agree, recheck the key. If you put grease or oil on the flywheel or shaft, it will shear again. If it wasn't tightened really tight, it will also.
Old 05-31-13, 03:38 AM
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When you went to replace the flywheel key, did you happen to take the whole motor off the tractor and then take the sump cover off? Possibly to figure out what happened when it sheared the key?
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