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AC710

Why is my 16 HP Briggs backfiring?

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AC710

I am ducking for cover when I shut off my 7016 after blowing snow for 30 minutes or so. I run it WOT for the blower, and throttle down slowly before shutting it off . When I turn off the key. it backfires VERY loudly, once. It starts okay, idles and runs fine and has good power. New carb that doesn't leak

I am thinking maybe carbon in the head? I don't have a lot of experience with these engines so I'm looking for ideas. Thanks

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rockfangd

I have a 7116 and I do the same. I always idle it down and let it run for a few minutes before shutting it down.

I do my shovel touchups, then go back and shut it down

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Bill725
11 hours ago, AC710 said:

When I turn off the key. it backfires VERY loudly

When carburetor engines are turned off, the ignition is grounded and stops the spark. As the engine continues to rotate an air-fuel mixture continues to be drawn into the cylinder and out the exhaust unburned. The exhaust is hot enough to cause the mixture to ignite in the muffler and cause it to backfire. This could cause damage to the muffler. As @rockfangd, stated let the engine cool down by letting it idle for a while before you shut it off and that should take care of it. 

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AC710
1 hour ago, Bill725 said:

The exhaust is hot enough to cause the mixture to ignite in the muffler

This engine has a vertical stack that gets really hot, and the backfire report is right up top. Sounds like that may be the answer.

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bruker1

I have a Prestige with the Kohler Command. It used to backfire too when I shut it off after throttling down. Also blew a couple head gaskets... Then I found out that Kohler recommends shutting it down at half throttle or higher. It no longer backfires or blows head gaskets. :)

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AC710
6 minutes ago, MARK (LI) said:

Does it have backfire preventer solenoid that is stuck open?

No backfire preventer on a 1976 flathead Briggs. I am learning that this is quite a common thing from this and other forums, with a variety of suggested solutions. I'm not doing much snow plowing so far, but will report back next time I do.

My 2008 Kohler Courage also tends to backfire if I cut the throttle quickly. Simple solution, cut the throttle slowly sm01. I suffered through hard starting on that engine for years until I finally learned the backfire solenoid was stuck partly open. Starts easily now that it doesn't have a backfire solenoid any more.

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rockfangd

I always made it a habit to idle my engines down and let them cool gradually. 

I guess it comes from all of the engines and turbos I have worked on over time.

I do the same with my JD 826. I ease into it, run it hard, then let it cool down before  I shut it down. 

To Date I haven't had the backfire issue in a long time.

And backfires can definitely blow out the muffler and or headgasket. Not something you want to have happen often. 

Edited by rockfangd

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AC710

Got a bit of snow today and used the blower

I let it idle for a minute while I cleaned out the auger and tried to determine why it threw the belt...

No after fire! "When all else fails, read the directions."

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