# slight problem/popping



## AnteDarvo (Feb 17, 2015)

i have an ariens 27" snowblower. model 921012 with a b&s 1150 series engine on it. i love this machine. but from day one, brand new in 2009, this engine has had a slight popping coming from the exhaust while the engine is running. it seems that the longer it runs, it pops a little more. at first, i thought it was a lean condition. click the choke closed a little, same problem. changed and gapped the spark plug. same thing. even readjusted the valves, same thing. now i'm thinking maybe a slightly weak valve spring. not really sure though. engine really runs great and the machine throws snow well. can anyone give me any other ideas. the engine is a briggs & stratton 15c134 0128 e8.
thanks for listening.


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## Pathfinder13 (Feb 28, 2014)

Pilot (low) jet may be partially clogged or undersized. That's about all I can think of that would cause it , but some others may know more than I for sure. It's one thing you can check though.


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## Ken05 (Feb 13, 2015)

Pathfinder13 said:


> Pilot (low) jet may be partially clogged or undersized. That's about all I can think of that would cause it , but some others may know more than I for sure. It's one thing you can check though.


 Very likely, ethanol in the fuel is notorious for gumming up pilot jets.


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## AnteDarvo (Feb 17, 2015)

i am going to pull the carb and thoroughly clean it, but, i use 91 octane non-ethanol fuel. i'm really not suspecting the ethanol problem. also, i always drain the carb and fuel tank every year when in storage. i do this on all my equipment.


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## Pathfinder13 (Feb 28, 2014)

I am unfamiliar with that carb, but on mine (honda clone)you can pul the pilot jet without removing the whole carb very easily. You may be able to save yourself some work look into that first ;-)


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## Loco-diablo (Feb 12, 2015)

AnteDarvo said:


> i have an ariens 27" snowblower. model 921012 with a b&s 1150 series engine on it. i love this machine. but from day one, brand new in 2009, this engine has had a slight popping coming from the exhaust while the engine is running. it seems that the longer it runs, it pops a little more. at first, i thought it was a lean condition. click the choke closed a little, same problem. changed and gapped the spark plug. same thing. even readjusted the valves, same thing. now i'm thinking maybe a slightly weak valve spring. not really sure though. engine really runs great and the machine throws snow well. can anyone give me any other ideas. the engine is a briggs & stratton 15c134 0128 e8.
> thanks for listening.


Greetings! I have the same exact blower and engine. I notice on mine that if i throttle down from full power to idle, mine makes a single big POP. It's been doing it since day one (2009). If I go from full throttle to OFF, it doesn't POP.
I have always run regular unleaded (87). When running at FULL while I'm using it, it makes no POPs though.. It runs great. It's just when i throttle down to idle.


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## Grunt (Nov 11, 2013)

AnteDarvo said:


> i have an ariens 27" snowblower. model 921012 with a b&s 1150 series engine on it. i love this machine. but from day one, brand new in 2009, this engine has had a slight popping coming from the exhaust while the engine is running. it seems that the longer it runs, it pops a little more. at first, i thought it was a lean condition. click the choke closed a little, same problem. changed and gapped the spark plug. same thing. even readjusted the valves, same thing. now i'm thinking maybe a slightly weak valve spring. not really sure though. engine really runs great and the machine throws snow well. can anyone give me any other ideas. the engine is a briggs & stratton 15c134 0128 e8.
> thanks for listening.


Welcome to the forum AnteDarvo. As others have stated, it could be a lean fuel condition OR the valves are not adjusted correctly. Briggs states that the valves have to be adjusted with the piston 1/4" PAST top dead center. The procedure is near the bottom of this page. If you did it this way, disregard my suggestion and concentrate on the carb. I hope this helps.

Engine Valve Maintenance & Repair | Briggs FAQ


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## Pathfinder13 (Feb 28, 2014)

Loco-diablo said:


> Greetings! I have the same exact blower and engine. I notice on mine that if i throttle down from full power to idle, mine makes a single big POP. It's been doing it since day one (2009). If I go from full throttle to OFF, it doesn't POP.
> I have always run regular unleaded (87). When running at FULL while I'm using it, it makes no POPs though.. It runs great. It's just when i throttle down to idle.



Open up the idle jet a little. It's that way because of EPA standards they want it to run a little lean. You get rid of the pops and increase your performance slightly because even the idle jet fuel mixes with main jet fuel and you gain a slight bit on top end torque. Not sure how much you will notice if at all, but it will throttle up and down smoother and no pops, and possible idle smoother with a slight increase in pilot jet size. Clean that spark plug too make sure the gap it at the right amount.

That said, must be done carefully with micro drills in a pin vice, you just gingerly twist the jet into the drill one size at a time after you figure out where you are to start. 

If you don't feel comfortable doing it, just leave it alone, a little pop won't hurt anything. It's just a little annoying when you know the cause and know how to fix it.


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## Kiss4aFrog (Nov 3, 2013)

I picked one up on ebay. You can also buy bigger jets but having a couple machines I figured it was cheaper for me to get the drill bits.


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## AnteDarvo (Feb 17, 2015)

mine pops too while shutting the engine down. i believe they call that after-pop. 
if i bring the engine down to idle and run it there for 10-15 seconds and then just shut it off, no pop. idling it down for those few seconds before shutting down allows the engine to clear itself of excess fuel.
i do have precision drills and pin vises for carb work. i've done alot of drilling on rochester q-jet's. too bad we don't have our precious adjustments anymore.
fixed carb settings. what a joke. maybe i will try to open the jet slightly, listen to the engine and watch the spark plug. 
i do miss our main metering and idle adjustments though.


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## enigma-2 (Feb 11, 2014)

My Ariens 24 Platinum was popping quite a bit (more then normal) last time I used it. Today I had to refill the gas and added a generous amount of Sea Foam. After I had finished the drive & before I got to the neighbors drive, almost all the popping was gone (it's always popped every so often, every since it was new last year).


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## AnteDarvo (Feb 17, 2015)

it's amazing. mine has been the same since brand new just like yours. a slight popping. you use sea foam and the popping stops. what are they doing from the factory. it almost tells you that one of the carb circuits coming from the factory is slightly plugged. it's usually the other way around. the poor gasoline, leaving fuel in carb while not in use, etc....plugs up a circuit, it will surge, pop, run better while choked or not start at all.
oh well, we'll just keep on fine tuning where we can.


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## hankster1 (Sep 10, 2013)

Try running on regular fuel. The octane might be too high for the engine. 
Hank


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## Loco-diablo (Feb 12, 2015)

Pathfinder13 said:


> Open up the idle jet a little. It's that way because of EPA standards they want it to run a little lean. You get rid of the pops and increase your performance slightly because even the idle jet fuel mixes with main jet fuel and you gain a slight bit on top end torque. Not sure how much you will notice if at all, but it will throttle up and down smoother and no pops, and possible idle smoother with a slight increase in pilot jet size. Clean that spark plug too make sure the gap it at the right amount.
> 
> That said, must be done carefully with micro drills in a pin vice, you just gingerly twist the jet into the drill one size at a time after you figure out where you are to start.
> 
> If you don't feel comfortable doing it, just leave it alone, a little pop won't hurt anything. It's just a little annoying when you know the cause and know how to fix it.


Thanks Pathfinder.. At this point I think i'm going to leave it alone. It's on it's 6th season since new. I've never had it serviced other that plug/oil and some minor repairs (cables) adjustments that i performed myself. After this season i plan on bringing it for a proper/professional service..ie carb cleaning/adj, belts, etc..
I'll mention it to my dealer when i bring it in. 
The pop is a little annoying though, but it runs fine.


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## enigma-2 (Feb 11, 2014)

AnteDarvo said:


> it's amazing. mine has been the same since brand new just like yours. a slight popping. you use sea foam and the popping stops. what are they doing from the factory. it almost tells you that one of the carb circuits coming from the factory is slightly plugged. it's usually the other way around. the poor gasoline, leaving fuel in carb while not in use, etc....plugs up a circuit, it will surge, pop, run better while choked or not start at all.
> oh well, we'll just keep on fine tuning where we can.


Dealer said they are set to run very lean on purpose. Something about fed standards, or something like that. (Wasn't listening like I should have).
He did stress to use mid-grade or premium gas however. Said he only uses premium in his own lawn equipment. Said it was more important with the with the newer engines. (Smaller ports, especially California CARB engines which have smaller ports still). 

And he told me which gas stations to avoid getting gas at locally.
[edit] remembered that he told me that certain stations were selling gas that had more failures than other stations. He suspected that those stations was selling gas with higher Ethanol content (either by accidient or on purpose). Basically the stations to avoid were the off-brands that sell for less.


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

My neighbor has a Honda with the same complaint. It happens when throttling down. More annoying than anything but he said it just started to do it this year.

With all the snow we have been having he does not want to take anything apart. I recommend trying a bit of Seafoam with each tank of gas. So far He says it has helped. It still does it but not as frequently.
That would certainly suggest some kind of carb cleaning is needed. Does not rule other the other things mentioned above too. i.e valve clearance, spark plug.


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## Snowhawg (Feb 20, 2015)

I have owned multiple Briggs engines on many different pieces of equipment. They all have that "pop" when closing the throttle down. It's normal, but not appreciated. As mentioned it has to do with how lean they set them from the factory to meet emission guidelines. You would have to rejet the carb to try and eliminate this. Sometimes opening the fuel screw is enough, but most are capped so you cannot easily adjust this.


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

My understanding is the "pop" is unburned fuel igniting on the hot muffler. Am I correct, partly correct or just wrong?


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## Loco-diablo (Feb 12, 2015)

So after 6 winters of the 'popping' since new, I had my machine dealer serviced this week for the first time and the popping appears to be gone. They said they cleaned the fuel system which included the installation of a carb kit. I'm not sure if valve adjustments were done, but she's running like a top!


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## Pathfinder13 (Feb 28, 2014)

probably had crud in the jet or emulsion tube holes , it can happen, it doesn't take much. Could have even been from when it (e- tube)was machined, and when they cleaned it it freed it up. Great to hear it's running smooth.


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## AriensSnowman (Dec 9, 2014)

_"Dealer said they are set to run very lean on purpose. Something about fed standards, or something like that." 
_
100% true for all power equipment. If it's a Briggs and it doesn't pop anymore, the dealer probably re-tuned the carb for you. A Husky dealer near me re-tunes ALL their equipment (trimmers, leaf blowers, etc.) because they run so poorly from the factory. Otherwise customers are always returning and complaining. There's a special tool needed for the fuel screw and once you simply open it up more, Bingo. Every Briggs engine I've used will backfire when closing the throttle from full to idle.


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## jenkinsm2 (Dec 7, 2014)

Is it possible the flywheel was not tightened to the correct torque when assembled? Would that cause popping out the exhaust?


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## Loco-diablo (Feb 12, 2015)

AriensSnowman said:


> _"Dealer said they are set to run very lean on purpose. Something about fed standards, or something like that."
> _
> 100% true for all power equipment. If it's a Briggs and it doesn't pop anymore, the dealer probably re-tuned the carb for you. A Husky dealer near me re-tunes ALL their equipment (trimmers, leaf blowers, etc.) because they run so poorly from the factory. Otherwise customers are always returning and complaining. There's a special tool needed for the fuel screw and once you simply open it up more, Bingo. Every Briggs engine I've used will backfire when closing the throttle from full to idle.


It never ran poorly, always strong and steady. It just would give that single 'pop' when throttling down to idle from full power. Going from full throttle to OFF, it wouldn't do it. Anyway, it ran like that for 6 years! I think I'm going to miss that pop!


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## orangputeh (Nov 24, 2016)

Pathfinder13 said:


> Open up the idle jet a little. It's that way because of EPA standards they want it to run a little lean. You get rid of the pops and increase your performance slightly because even the idle jet fuel mixes with main jet fuel and you gain a slight bit on top end torque. Not sure how much you will notice if at all, but it will throttle up and down smoother and no pops, and possible idle smoother with a slight increase in pilot jet size. Clean that spark plug too make sure the gap it at the right amount.
> 
> That said, must be done carefully with micro drills in a pin vice, you just gingerly twist the jet into the drill one size at a time after you figure out where you are to start.
> 
> If you don't feel comfortable doing it, just leave it alone, a little pop won't hurt anything. It's just a little annoying when you know the cause and know how to fix it.


I have this popping also with a gx240 engine on a honda hs828. It starts easy and runs great at full throttle. only pops when i decelerate quickly.

was wondering if this is a lean condition, could i put a pilot jet from a 928 in the carb? or could it be a faulty or undersized O ring on that pilot jet. i recently replaced that O ring from a O ring set I got on Amazon. nowhere in the manual does it give the O ring size but the ring i put on looked just like the old one.

this seems to be a common problem with the honda's.


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## RIT333 (Feb 6, 2014)

If it didn't pop before you changed o-ring, then that is probably your problem, otherwise, it is a lean condition, and put in a larger size jet.


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## orangputeh (Nov 24, 2016)

RIT333 said:


> If it didn't pop before you changed o-ring, then that is probably your problem, otherwise, it is a lean condition, and put in a larger size jet.


do you mean pilot jet or main jet? 

I don't know if it popped before. I just got it and when i was cleaning carb and took pilot jet out the O ring was stuck in hole and torn. i replaced it with a generic. it fit on the pilot jet but i did notice the jet went back in very easily. usually it goes mostly in then you have to kind of pop it in the last few mm's.

What i will do next is take an oil ring off one of my spare 240 carbs.if that doesn't work I'll put a 928 pilot jet in and see if that helps. 

thanks.


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## rslifkin (Mar 5, 2018)

A little popping on a sudden reduction in load isn't a big deal. If the governor is throwing the throttle fully closed for a second, you can end up with decel pops like a car or motorcycle can get.


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## orangputeh (Nov 24, 2016)

it turned out to be the O ring on the pilot jet.

i took a pilot jet out of an old HS80 carb that had a good O ring and installed it and now it runs great. no backfiring , no popping , and no minor hunting and slight popping at idle.

all because of the tiny O ring. I bought an assortment of O rings online and though one of their small ones that looked like the exact size would work but none of them did.

the sad thing is the Honda dealer won't sell that O ring. You have to buy the pilot jet for 17 bucks . I think boats.net has them for 11-12 bucks but that is not the point. I wish I could just buy these O rings by the dozen. If anyone knows where I can just buy these O rings , I will buy you a beer.


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