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12HP Briggs backfires and kicks


theboogins's Avatar
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10-04-04, 12:12 PM   #1  
theboogins
12HP Briggs backfires and kicks

Solved my no spark problem with a new coil and on the first pull it fired right up with the carb primed with a little gas-only ran for 1 sec or so but sounded fine. I re-set the carb to factory specs and pulled again-first pull I got a loud backfire through the muffler along with a puff of smoke from the top of the carb. I pulled a few more times with pretty much the same result except that sometimes the rope would grap and there would be a loud noise and it was like the motor was hitting something but it spins pretty easy by hand.

Is the backfire sign of a clogged carb? or what.

Thanks.

J. Boggs

 
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10-04-04, 08:18 PM   #2  
Azis
Recheck your coil to make sure it is tight and still in one piece.How did you set the air gap on the new coil? Did you loosen the flywheel nut during your repair or trouble shooting of no spark? Either way you may want to have a look at your shear key while under the hood.
See if ya find anything there and post back if not.

 
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10-04-04, 10:38 PM   #3  
Yep, sounds like the flywheel key has sheared.


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10-05-04, 06:23 AM   #4  
theboogins
You guys are good...

Yep, the flywheel key was sheared and the wheel has spun. Mine has the spin-on tightener that connects to the pull cord-I guess I didn't get it torqued down enough.

As to the air gap, I tried a trick the parts counter guy told me about and simply stuck a business card between the coil and the wheel and tightened it down. I know, not very scientific, but I went to Auburn.

It purred like a kitten for the 1/2 second before the key came apart.

Thanks.

J. Boggs

 
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10-05-04, 09:23 AM   #5  
Azis
Sounds like you set the air gap to between .010 and .015, Scientific enuff
Glad ya got it.

 
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