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hoskinsb

No Spark in my B112

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hoskinsb
I am in the process of rebuilding my B112. When I installed the engine and all the acc. I tried starting it and it coughed a few times then nothing. I pulled the plug and checked for spark, nothing. I have replaced the coil, points, condenser and spark plug. When reading the past topics on "no spark" I read several replies that it might be the flywheel key. This is the only thing I have not checked. I did remove the flywheel in order to paint the motor.The starter pully still turns the engine over. My questions regarding the flywheel key are as follows: If the key is partially sheared would there still be spark, just out of time? Could the key shear if the engine never truly fired? Can it be anything else? Thanks, Brent

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arjr111
Hi Brent, if the flywheel was replaced and torqued to specs., IMO it would probably take a backfire to shear it. A partial shear, that displaces the flywheel only slightly, would probably still allow spark to be produced (but it may not start or run poorly). Check your wiring and make sure you are not grounding out. Start at the ignition, harness, and follow each wire to its destination......Good luck Art

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hoskinsb
Thanks Art, I checked all the wiring, found nothing shorted. Out came the engine and sure enough the flywheel key had been sheared, it had spun the flywheel a quarter turn on the shaft. Put a new key in and it started on the second crank. Thanks again for the help, Brent

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roma3112
one thing i would add is to make sure the flywheel is toequed to spec, i had a heck of a time with my old cast iron 12hp briggs. i rebuilt the engine and did the old hand tight and 1/4 1/2 turn well guess what it musta sheared that key 4 times giving me the same symptoms you described. If you have not buttoned her up already throw a torque wrench on her and check it. john

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