My engine is backfiring

I have a Dewalt 4200 psi, 4 gal per min with a Honda 390.

Today it started backfiring whenever I let off the gun. Any idea what is causing this?

I did try searching but could not find an answer.
Yanks
Jim

Are you using higher octane fuel in it? Or just the cheap stuff?

Also, Check the spark plug. If it looks fine, check the gap. Gap too big, weak spark, fuel ignited at muffler.

If you’re using fuel with ethanol in it ignites “faster” than non ethanol gas and some can make it through to the muffler is the gap is funky.

Oh… and throttle. Open it all the way up if it’s not.

I am using cheap gas as I always have.
I will check the plug and gap.
Thanks guys
Jim
Ultra Wash USA

Whens the last time you checked/cleaned/replaced air filter? Some of these little engines get build up in the carb from ethonol so some seafoam goes a long way as well.

I will changel the filter and plug tomorrow

Exhaust leak. Check muffler…

Mine was doing that last week. I would let off the gun and notice a loud backfire. Come to find out, the muffler was giving up on me where it was welded.

I got one from Amazon a couple days ago. Fits perfect.

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