# Exhaust Backfire on quick deceleration.



## GMJim (Feb 12, 2017)

I'm an auto mechanic but not that familiar with small engines. Before I get my tools out to deal with the problem I thought I'd ask here. This is a 6 year old machine 1330SE with a 342CC engine and when I decelerate quickly it will backfire out the exhaust. If I do it slowly no issues. This has done this since brand new and I felt I'd break it in a few hours and see if it continued. We haven't had a lot of snow here over the last 4 years so usage has been seldom. Anyway I thought maybe the carb is set too rich or lean or the valves are set up too tight? Any ideas?
Thanks
Jim


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## 43128 (Feb 14, 2014)

if it otherwise runs fine dont worry about it. unfortunately due to epa small engine emission regulations all new small engines are set up to run run as lean as possible. the epa takes all the joy out of life! fortunately, if you have a honda clone type engine such as an lct, powermore, loncin or one of the newer briggs and stratton honda clones you can usually remove the bowl nut, and remove the brass carburetor jet and open it up a bit


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## dhazelton (Dec 8, 2014)

Same principles as a car engine - too lean. If it bugs you, you can probably pull the main jet and ream out the holes a bit.


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## GMJim (Feb 12, 2017)

Thanks for the replies guys. So no adjustments? Just jet size mods? Oh well I can live with the exhaust popping as long as it's normal. I just need to decelerate gradually to avoid the popping. I don't want to blow the muffler off it.
Jim


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## orangputeh (Nov 24, 2016)

GMJim said:


> Thanks for the replies guys. So no adjustments? Just jet size mods? Oh well I can live with the exhaust popping as long as it's normal. I just need to decelerate gradually to avoid the popping. I don't want to blow the muffler off it.
> Jim


was wondering about the same thing and was worried that it was a timing thing or a valve problem ( which maybe it could be )

but have seen this on several other Honda machines so maybe what has been mentioned is the problem. also, if i decelerated gradually , nothing happens as well.

Jim, there is an interesting topic on re-jetting the carbs. I may do that because of added bennies or more power and smoother running.


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## GMJim (Feb 12, 2017)

Just got off the phone with a buddy of mine who has the same machine and he says his does exactly the same thing. As 43128 said, it's probably tuned for emission regs and it has it's trade offs. It runs strong, I just need to go a little slower turning the rpm's down.
Thanks everyone for the feedback.
Jim


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## vinnycom (Nov 6, 2017)

or see if they have an aftermarket adjustable carb


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## Toro-8-2-4 (Dec 28, 2013)

Just to confirm you are lean pull the plug and inspect it. This is pretty much how those who open the jet gauge if they are too lean or rich.

For the Preditor engine, a Honda clone, there is an aftermarket adjustable carb main jet on Ebay.

One of our members here is a machinist and sells them along with oil drain plug adaptors to make your own EZ drain.


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## Money_man (Feb 16, 2015)

I have a 1130se with the 342cc B&S, it also pops when backing off the throttle. I just take it as normal.


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