Backfire Through Carb

Put a fuel psi gauge on that you can see while driving and check psi while under load. Starts and runs fine, but when under a load or accelerating hard above 2000 rpm it starts backfiring through carb? What is the cause? And cheapest and easiest solution?. Re: Backfiring through Carburetor in reply to Phil Simmons, 10-10-2007 16:15:29 Clean the plugs, turn off the gas and see if it will start by squirting starting fluid into the carb. The vapor enters the carburetor (24) through the specially drilled port (20) in the ventura below the throttle valve (22). Engine is backfiring through the carb when I accelerate and looses power. I even removed a valve cover to make sure my rotor was hitting the dist cap at the right spot. This is a most important indicator of what is happening. Check all vacuum connections as well as the gasket mating surfaces. Once running they seem okay but will back fire when restarted. in park it idles smooth but if i try to rev it quickly i get this monster very impressive backfire through the carb. my thoughts are the intake valves are not seating fully but a shop just installed a new head less than 600 miles ago. Cleaveland won't start, backfires through carb. The performance may not be optimum due to signal strength or restrictions, but if the jetting is close for one, it will be close for the other. after giving it a shot of starting fluid i got it to run. Low Carb Taco Salad | Low Carb MavenA tasty low carb taco salad using wholesome ingredients is naturally low in carbs, easy to prepare, and absolutely delicious! Use lean ground beef or turkey in this nice twist on Taco Tuesday!. If I give a shot with the accelerator it stumbles. Your advice would be most welcome. Real backfiring is actually the bike "spitting up" in a sense, backwards through the carburetor or intake. It cranks right up and idles fine, but once I press down on the gas it backfires through the carb. Nikki Carburetor for Briggs. I had the carb rebuilt a couple of years ago with a new sleeve and dissimilar slide by a guy I trust. In this edition of Maintenance Monday, we're answering a question from Dena in Mississippi. The quad will now idle fine, and no more backfiring through the carb. Starts up and idles good, once you start giving it throttle it acts as if its starving for fuel. Carburetor Hats. Next I'd have a look at the carburetor, take off the bowl and see if its all gummed up with crud, if so clean it. Find descriptive alternatives for backfire. When you decel you are getting unburned fuel igniting back through the carb. I have brought the boat into my local mercruiser dealer and we have not been able to overcome the problem, even with tech support from Mercruiser. Here's the scoop. 2 cycle engine backfire thru carb, 2 stroke back fire through carby problem, chainsaw backfires, chainsaw backfires through carb, mcculloch strimmer backfires through carb, sthil chainsaw backfire starting, stihl chainsaw backfires, what makes a weed eater backfire, why would a 2 stroke back fire. ran great for a few months. The fault is similar to the one shown by a carburetor with a faulty accelerator pump. Your advice would be most welcome. Hey all, I work for a fleet shop and we have a lifeguard ATV its a Kawasaki brute force 650. The carb is a Holley 750. Didn't fiddle with any adjustments besides float because it ran fine before. Page 1 of 2 - Backfire Through Carb/no Power? - posted in Problems, Questions and Technical: Mini Clubman 1275 GT, 1979. I had a really odd problem of backfiring through the carb when I put any load on the engine- you could drive, but you have to very slowly accelerate or POP POP goes the carb. It was running fine, I parked it for a few weeks and now it will not idle unless I have the choke pulled half way out, even after it warms up. On the intake side, regular backfires can lead to engine damage. time to find the leaky plumbing. It runs beautiful while its still cold, then as soon as it warms up it just backfires, loud. The concept is roughly similar in vehicle engine systems. engine and drivetrain backfire through the carb By blackrado, June 16, 2016. (I have top part of air tube disconnected from air cleaner). the carb was rejetted after installing the new pipes). I read some forums which pointed towards the carb, so I swapped over to my spare carb - did the same thing. my next step is to change the intake/exhaust gasket. You may have to register before you can post: click the register link above to proceed. Re: what causes back fire through carb? It's puzzling to figure out why there would be pressure in the cylinder at the time the intake valve opens. Footage taken from Holley Carburetor Installation & Tuning DVD. Buying a new one without verification is just a waste. Recently I removed the rear wheel from my motorcycle and had to exert pressure on the front pipe in order to extract the axle bolt. points, condenser, distributor cap, rotor, spark plugs and wires, and replaced ALL the vacuum lines, and even the idle stop solenoid. com is dedicated to the Honda CB750 SOHC and DOHC motorcycles and to their owners who love to ride, restore, and customize them. It looked like it was burning off some type of residue. The backfiring and run on are both characteristic of timing problems. It started it up in the garage and it seemed fine. diet and a Holly 750. 016 initially to allow for expansion while warming up the engine to do a hot setting. When I am at low rpm's and gas on it it will backfire thru the carb. , Installed MSD, and 2 diffrent rebuilt carbs. Backfires may also be caused by a leaking hose, faulty plugs or the brand of fuel being pumped in. Carb removed, cleaned, all passages seem clear. Your rebuilt carb may still be a turd (or even a bad fuel pump) but backfiring through the exhaust is most often fuel/rich related. There are can be other causes but more information is needed to help point you in the right direction. Recently I removed the rear wheel from my motorcycle and had to exert pressure on the front pipe in order to extract the axle bolt. Under this circumstance, the low speed fuel circuit needs to be adjusted. Does anyone have any idea on why it may be backfiring?. Re: Backfiring through Carburetor in reply to Phil Simmons, 10-10-2007 16:15:29 Clean the plugs, turn off the gas and see if it will start by squirting starting fluid into the carb. When I come to a stop the idle is off, it almost feels like it is mis firing. Mixture alone won't cause the backfire through the carb. Popping and backfiring CB750. It was a sheared flywheel key, but that does not seem to be your problem. Rough idle, low power on acceleration, backfire on acceleration along with black smoke, hesitation Out of the blue the 75 FJ40 started this behavior after starting it up two days ago. Came out again today and it fired right up on half throttle but was rough in idle and eventually died. This can occur due to a faulty intake valve or intake manifold that's causing extra air to leak into the system. 2 and that is a clockwise rotation. here is a list of all the things i have fixed. 3) Replace the power valve. Backfire through the Carburetor. I would not be surprised if the carb is not set up correctly. How to adjust the mixture screws on your carb. What is causing the backfire through the carb? I am working on a car that has sat in a garage for quite awhile. Re: Onan 5BGEFA26100P NO start, backfires thru carb In general when I work on cars if a bolt is stuck I apply heat, works better and faster than penetrating oil. It does hang up in the revs before dropping back down to idle when you rev it. A backfire could also occur if the carburetor has too much air in the mixture. Backfiring through carb. Inquire with equipment manufacturer about increasing engine-cooling air volume by decreasing air restrictions. One morning I made a short trip and stopped ,when I went to restart it was popping back through the carb , replaced the cap and good to go. Tips to Prevent Backfire. I should mention that I have replaced the original carb with a Ford 2100 several years ago. The motor is only used 2 seasons. It did sit out in some snow and the tarp I had over the engine blew off and there was a pile of snow on the engine,breather cover and fuel tank. Carburetors. When I set it at 10 degrees BTDC, it fired right up. Now, when I get past partial throttle and crack the secondaries the car bogs, bucks, and backfires. If backfiring occurs through the carburetor then adjust the idle mixture screw out another 1/8 turn. Pumping the footfeed during this time simply prolongs the agony, as the accelerator pump will pump the fuel into the engine, but in amounts insufficient for starting. Low Carb Taco Salad | Low Carb MavenA tasty low carb taco salad using wholesome ingredients is naturally low in carbs, easy to prepare, and absolutely delicious! Use lean ground beef or turkey in this nice twist on Taco Tuesday!. But since most of those guys are out wheeling while im stuck in my office today, see if this helps. The left runs great but the right putt-putts back through so it isn't a carb issue. Borrow a carb and swap. You should be using an RJ19LM or J19LM spark plug with a gap of. To clean the carb, personally I think it's best to take it off the bike, pull it apart and clean it throughly and don't forget to check the float. But this kind of damage appears to be pretty rare, so unless it's happening pretty often, I wouldn't be too worried about the occasional backfire on my ATV. If you are getting backfiring through the carb there are some other things you should check too. Backfiring through carb, power surging, some backfiring through exhaust. If it does not work, look down your carb (with the engine off) and see if it's shooting gas when you work the throttle. I think it may be ignition, timing, or carburetor related. I'm having a problem Identify the cause of a rather annoying and potentially dangerous problem. Earlier carbs don’ have this. Hey all, I work for a fleet shop and we have a lifeguard ATV its a Kawasaki brute force 650. Use a new intake to carb gasket. If you don't know how to test, Take it to a mechanic. Its not really a backfire though, more like a muffled popping sound, I guess backfiring is the easiest way to describe it. my thoughts are the intake valves are not seating fully but a shop just installed a new head less than 600 miles ago. I rotated the carb so I could access the pilot screw. i acquired an 84 gl1200 a few months ago, and have been workin on it night after night to try and get it finished. I did a search and found a comment stating "If the engine backfires through the carburetor, misses, cuts out or quits running, the main jet is lean. 0 longblock Victor Jr. When she drives I get a pop through the exhaust and a pop through the intake. now it is backfiring like crazy. Its back firing through one carb more than the other one and back firing through the exhaust. they are solid lifters as far as i know. Backfire is a condition described as a loud bang, poof, explosion, etc. There is gas smell in oil. Backfiring that results from damaged wiring disrupts the ignition's timing, which causes a build-up of air and fuel in the engine. Some people think you're supposed to turn the idle mixture screws all the way in, and then back them out 2 1/2 turns. C3 Tech/Performance - Backfiring through carb - I have a 1977 vette that I inherited from my uncle. backfiring through the carb (self. it is a 72 454 that now has a holley carb and headers. its not starting and when it does go to start it backfires. If the timing is off it will backfire through the carb and also if it is cross wired (firing order wrong) it will backfire through the carb. After that the motor will backfire through the carb. It cranks right up and idles fine, but once I press down on the gas it backfires through the carb. You did not send a model number, so I don't know if the information I am sending you will be helpful. You'll get more input from others to confirm but I believe you must make a wiring connection during timing check to get the distributor into base timing mode. Popping and backfiring CB750. The coils fire both coils at the same time. It looked like it was burning off some type of residue. Car backfires through the carburetor are sometimes caused by a lean air/fuel mixture. I even removed a valve cover to make sure my rotor was hitting the dist cap at the right spot. A good balance is essential for an optimal combustion and functionality as too little or too much could bring on backfires. So I crack the throttle and it backfires through the primaries. In all cases, moving the jet further into the carb leans the mixture, while moving the jet further out of the carb richens it. My mechanic says the carb needs a rebuild but says he does not have time for it. i have looked straight down the carb to watch the accel. it also surges at idle in gear. Maybe a sticky or dirty intake valve, a timing issue, a chipped valve head It could be detonation (gas ignites while the intake valve is still open) But if the intake valve is closed, it can't happen. Troubleshooting Your Holley Carb August 2, 2017 Wayne Scraba Fuel Delivery , How-To and Tech Tips , News 1 Holley carburetors find their way onto countless vehicles, from race cars to hot rods to delivery trucks, and for good reason: They're the standard of performance, and without question some of the most popular and easily tunable. 0 longblock Victor Jr. What is causing the backfire through the carb? I am working on a car that has sat in a garage for quite awhile. I bought my boat last year and was never able to get the boat over 30mph which is when it would backfire through the carb. For that period it was GM's answer to a carb and I think they worked better than a carb, but they came with their own problems. And I can also sometimes hear some backfiring through the exhaust. Then using the carbs pump rod, pump fuel through nozzle by hand until a good stream is obtained. I'd pull the bowls make sure it's all clean inside. I"m assuming this is an ignition timing problem, but if it is, do I need to advance, or retard it? It has a Wico XH magneto that I put new points, and coil in a year ago. Backfiring through carb, power surging, some backfiring through exhaust. I have a holley 600 on it and this is happening with the choke partially open and completely open. I did a search and found a comment stating "If the engine backfires through the carburetor, misses, cuts out or quits running, the main jet is lean. We have two Deere 345 lawn tractors identical in every way, one you need to let idle for a bit or KABAM, the other one never does backfire. I have a 2006 Precedent with the FE350 engine. When the engine was started again, it backfired constantly through the exhaust. Ordinarily, backfiring in the intake is an overlean condition. There are multiple ways to stop a motorcycle from backfiring that vary from inspecting and properly maintaining certain parts of a motorcycle to adding or replacing specific fluids. Blip the throttle a time or two and observe the results. I am working on my 1973 ford galaxie 500 it has a 400 big block and for the most part it runs fine but when you really put your foot in the gas it hesitates and backfires through the carb. If you notice a change in idle or how it runs you may have a leak which creates a lean environment which you experience as the backfiring through the carb. I'mpretty sure Tim's is a throttle body injection like mine. i have a 83 ford mustang gt and i took all the smog stuff off and changed carbs. The second most likely cause is a carburetor that is not adjusted correctly. Quote Reply. For a backfire through the carburetor to occur, a cylinder must fire while an intake valve is open, creating a path for the explosion to travel through the intake back to the carburetor. If i ease on the throttle it will rev but it sputters and will backfire through the carb. To clean the carb, personally I think it's best to take it off the bike, pull it apart and clean it throughly and don't forget to check the float. A faulty condensor can cause backfiring through the carb. so wanting to get rid of this condition entirely i when stage 1 arlen ness big sucker aircleaner, cvp premium rebuild kit of which i used. Posted: Sat Mar 16, 2019 8:23 am Post subject: Backfire through carb - 1966 1300 with Kuhltek cast iron 009 distributer (points & condenser) and new EMPI 30 pict 1 carb. When you go to full throttle you are asking for max fuel. Timing is 100% correct. Carburetor Hats. Maybe a bad carb to intake gasket. I have a 1996 boat with a 5. RPM goes up a little then down significantly and the truck seems to be starving out then it will backfire through the carb and catch back up. Hi All Great site, lots of good reading, and helpful members! I have a 1990 YFM 2050 Moto 4 Quad with a new somewhat annoying backfire issue. My 01 1200C backfires through the carb on light load with the throttle slightly open. Check your anti-backfire valve (It should be a small can shaped object with hoses running to the front carb boot and the front gas petcock vacuum hose). Almost all backfire situations will have other symptoms attached to them such as a Check Engine Light illuminated. If the engine responds quickly with a smooth blast and no backfiring through the carburetor, you have your idle mixture right. The car will start to crank but then backfires a fireball through the carb and leaves a small fire burning in the carb. I bought my boat last year and was never able to get the boat over 30mph which is when it would backfire through the carb. 1967 - 1972 F-100 & Larger F-Series Trucks - Backfire through Carburetor - Hello All, new to the forum and have read alot of good posts. I rotated the carb so I could access the pilot screw. 5 Must Do Canadian Rides. so, it should work for you. I did check and set the gap when I installed the plugs. It would produce very little power. Then using the carbs pump rod, pump fuel through nozzle by hand until a good stream is obtained. I have topped up the carbs with damper oil (from Moss) and the timing appears correct - but it still does it. points, condenser, distributor cap, rotor, spark plugs and wires, and replaced ALL the vacuum lines, and even the idle stop solenoid. If not enough fuel is getting to the engine the opposite may be true. Last Swedish road test dated 2010 so possibl. diet and a Holly 750. If the engine responds quickly with a gratifying blast and no backfiring through the carburetor, you have your idle mixture right. Terms often used are: Stuttering Hesitating Running Rough etc etc. the told me if it gets worse try a new carb. Turn it clockwise until it lightly seats (till it stops) - count how many times you've turned it (so you can put it back to it's initial setting if necessary). I assume that its' been re-jetted. Some people think you're supposed to turn the idle mixture screws all the way in, and then back them out 2 1/2 turns. Feels like a chain brake is on, and I've tried various carb settings with no success. The largest 4Runner community in the world. Well if timing is way out, and it andvances too far on full throttle would cause it, so a dizzy regraph may be the go, or is the dizzy shaft etc, just worn out. i have looked straight down the carb to watch the accel. My problems is when I try to rev the engine it just dies. I had a really big backfire getting on the freeway one day and it hasn't really been rideable since. With that said, i know for a fact ignition timing is dead on i have timed these engines many of times, and i double and triple checked it. Adjust idle mixture as shown above, problem #1-fix #3 4. I would not be surprised if the carb is not set up correctly. If the car has been setting for a while, the carburetor float valve may be sticking. First thing that came to mind was a partially sheared flywheel key, causing the engine to be a little out of time. I have been changing the carb jets and doing a lot of tuning, but the backfiring started before I even touched the carburetor. What is causing the backfire through the carb? I am working on a car that has sat in a garage for quite awhile. What are the most common causes and cures for this problem on a fuel injected twin cam motorcycle? From Our Friends at DynoJet Popping on deceleration is due to unburnt fuel being ignited in the exhaust. Not as noticeable at idle but gets worse as RPM goes up. If it"s not the timing, what else should I check? I"d appreciate any help. Don T: I hope you read this before you get back to wrenching. Lower engine speed slowly 2. So, the popping you are hearing is not back-firing. This after-fire is a by-product of backfiring through the exhaust, something that was a common sight in older car models. Don T: I hope you read this before you get back to wrenching. Hi, Newbie here. With that said, i know for a fact ignition timing is dead on i have timed these engines many of times, and i double and triple checked it. I also pulled the plug and it was really black. pump action while it running with both carb(the original one and one that was rebuilt) and a facefull of backfire (much to the. Once I put it. Listen here: John Deere Maintenance Monday: Backfiring lawn tractor engine. Generally, there are a variety of ways it gets there, and a variety of things that can make the backfiring worse. I use the restore in my snapper, it keeps the horrable oil burning smell away but it just covers up the problem. Going to the hole closest to the pump puts less fuel in and going toward the connection to the throttle increases I think. Then it started again, backfiring upon operation, spewing gas out the carb and then backfiring when shutting it off. Backfiring on deceleration is caused by a lean fuel mixture. Car has 15k miles on it and has been perfect until this!. My John Deere lawn more just started backfiring through the carburetor. Pull the front cover, grab the flywheel and pull up/down to see if the main bearings are shot. Check the vent plumbing to be sure this is the case, if you are getting manifold vacuum to the bowls it will idle bad and do all kinds of funky things through the RPM band like backfire through the carbs, exhaust, stall and restart etc. #303196 - 03/24/04 12:47 PM Carb BACKFIRE! on hard acceleration I either get a carb backfire or popping in the exhaust feels like it wants to backfire through. It generally makes a loud sound, like a gunshot, and occasionally is accompanied by a visible flame. Remove this, and the jet adjustment mechanism is exposed. when it spits and backfires is when i pull the choke. This means that fuel is getting ignited before the cylinder. Do aftermarket pipes backfire? A backfire or “lean misfire” on deceleration is primarily attributed to an improperly tuned engine. From reading here I have learning that this is more of a mis-fire and the backfiring is actually a lean mixture condition. I have topped up the carbs with damper oil (from Moss) and the timing appears correct - but it still does it. The loud explosion of unburned air/fuel mixture that is ignited in the exhaust manifold, usually upon deceleration. A carb will backfire under either a lean condition, as in an adjustment, or a malfunctioning accelerator pump. 016 initially to allow for expansion while warming up the engine to do a hot setting. I read some forums which pointed towards the carb, so I swapped over to my spare carb - did the same thing. So rebuilt the carb. While cranking it, it is "popping" / backfiring through the carburetor pipe, not consistently, but fairly regular. gator spitting threw carb and backfiring i,m working on a gator that is spitting fuel out the carb. Its back firing through one carb more than the other one and back firing through the exhaust. I have a Scag Cougar with a 27 hp Kawasaki FD750 S04 (with 350 hours) that idles fine, and drives fine, but a few minutes after it's working under load, mowing, it starts to slow down then backfires non-stop, till I remove the load. Turn the ignition key to RUN BUT DO NOT CRANK THE MOTOR. Kawi FD750 backfires under load. #303196 - 03/24/04 12:47 PM Carb BACKFIRE! on hard acceleration I either get a carb backfire or popping in the exhaust feels like it wants to backfire through. The engine will rev well in neutral. Cam design: Long duration cams with early opening intake valves can contribute to backfiring. Went to a smaller pilot it i have it set up pretty good right now. The plugs looked lean again, like they did before I increased the jets when I first got it running. When you go to full throttle you are asking for max fuel. Does it do this anytime or only when you try to blast from idle? If you want to sort out the inner motor from carb working, a compression or leak-down test will tell you if the intake valve is open. OBD1 chevy 5. If the timing is off it will backfire through the carb and also if it is cross wired (firing order wrong) it will backfire through the carb. I was wondering if anyone could be of some help- My 2005 Polaris Sportsman 700 is backfiring on deceleration. Re: I'm lost, Backfires threw my Carb. Almost all backfire situations will have other symptoms attached to them such as a Check Engine Light illuminated. Right off of idle, somewhere in the 900-1000 RPM range it seems to backfire through the carb into the air box. I got it last year and in the last few months have been working on it to get it running better. I follow the 3 min, 3 mile warm up faithfully with my ride. You may have to register before you can post: click the register link above to proceed. Note: Backfire and afterfire through the carburetor will not harm the engine at all! Find out the most common causes and possible fixes for engine backfire and afterfire. Deceleration Backfiring. A good balance is essential for an optimal combustion and functionality as too little or too much could bring on backfires. I replaced the gas and I am able to have it run at a high idle, however when I turn the idle screw down it starts popping in the exhaust. You may have to register before you can post: click the register link above to proceed. This is a discussion on [SOLVED] Engine timing on Briggs and Stratton engine within the Small Engines forums, part of the Tech Support Forum category. Runs clean everywhere else, no lag or stutter. Case closed, the machine shop is putting an insert, not a helicoil, in to repair the threads and no head replacement necessary. OBD1 chevy 5. There are many things to check going forward from here. #303196 - 03/24/04 12:47 PM Carb BACKFIRE! on hard acceleration I either get a carb backfire or popping in the exhaust feels like it wants to backfire through. I have a 1988 350 moto 4 that starts and idles great. As a guest you can view the forum and photo galleries, but you have to register before you can post or view attachments. i removed the fuel pump that was threaded in, and put in a 1/4 inch brass nipple. These look like a carb but are far from it. 2 cycle engine backfire thru carb, 2 stroke back fire through carby problem, chainsaw backfires, chainsaw backfires through carb, mcculloch strimmer backfires through carb, sthil chainsaw backfire starting, stihl chainsaw backfires, what makes a weed eater backfire, why would a 2 stroke back fire. The jury is out on how much damage backfires due to the riding lawn mower engine. 350 backfires through carb; Welcome to Club Hot Rod! The premier site for everything to do with Hot Rod, Customs, Low Riders, Rat Rods, and more. Inquire with equipment manufacturer about increasing engine-cooling air volume by decreasing air restrictions. I think the general theory was that the combination of my old carbonized plugs (old carb set way too rich) and worn out ignition bits. Note: See information regarding re-bushing and carburetor replacement below. i cleaned the carbs good and boiled the jets out, checked the floats, repaired one of the diaphragms etc. NO!, it just kept backfiring at both ends at about 2500 rpm (mainly through the carb). This condition may be caused by:. I think it may be ignition, timing, or carburetor related. Starts up and idles good, once you start giving it throttle it acts as if its starving for fuel. 454 Backfires - Problem Identified Hello All - Newbie Here - wanting to share a recent find. Backfire threw carb 06-28-2018, 01:00 PM Have had my 06 R* since new,and on the dyno to make sure new jetting isn't too lean (168 main and 38. The older method involved a check ball. I"m assuming this is an ignition timing problem, but if it is, do I need to advance, or retard it? It has a Wico XH magneto that I put new points, and coil in a year ago. Read More Asked in Chevy 350 , Chevy 305 , Timing. This, in turn allows some unburnt fuel to get into the exhaust pipes. backfire through carb I was having backfiring up through the carb really bad last year and it ended up being either a couple bad (new) spark plugs or i put too much anti-seize on them and they were not grounding to the block. backfiring through the carb usually happens when it is not getting enough fuelmaybe more liberal with the choke and a little richer on the idle circuit. They will start right away with a little shot of starting fluid. Fresh air is drawn in through those tiny holes and provides sufficient oxygen to ignite the unburnt gases inside. Used 3 timing lights , its does seem odd , btu we advance the timing and it pulls to 10 lbs real fast no problems dosnt matter what rpm range its when it hits 4 psi with the timing set at 40 it backfires , 48-50 no problem 44 its misfires a little ,Its real weird. Still have the surging and. Rough idle, low power on acceleration, backfire on acceleration along with black smoke, hesitation Out of the blue the 75 FJ40 started this behavior after starting it up two days ago. they put a new coil on it it stopped backfiring. pump action while it running with both carb(the original one and one that was rebuilt) and a facefull of backfire (much to the. I have been changing the carb jets and doing a lot of tuning, but the backfiring started before I even touched the carburetor. The symptoms were always the same. Pull the front cover, grab the flywheel and pull up/down to see if the main bearings are shot. 5 hp B&S willnot runafter winter it is backfireing through the Carby & air filter. It's like if this thing had a distributor, I'd swear it was way too far retarded or 180 off. Can anyone help me please or point me in the direction of someone who can please. If it's too far retarded you can get backfiring through the carb. So, the popping you are hearing is not back-firing. I have just got done rebuilding my carb well I actually purchased a new OEM carb and now I have a small issue with my engine it backfires through its single carb when at just over half throttle. Sputtering and misfires may result. Causes and Cures for Popping on Deceleration There's a lot of discussion about popping on deceleration. This outlet joins to the adjacent #2 carb which has a similar outlet on the side (and passage to the bowl chamber) plus it has a brass fitting above the outlet to vent to the outside.