Ah, the dreaded snowmobile backfire. Are you having trouble dealing with snowmobile backfire? Are you looking for ways to quickly and effectively put an end to this annoying issue?
Well, we’ve got you covered!
All the snow, the crisp air, and the blaring sound of a snowmobile backfiring- it’s enough to make you want to curl up in a ball and cry. But don’t worry – we’re going to show you a few simple tricks to deal with it easily and effectively.
In fact, with a few simple steps, you can have your snowmobile purring like a kitten in no time- and maybe even have a laugh or two along the way! So, buckle up and get ready, because we’re about to take a wild ride into the world of snowmobile backfires!
Snowmobile Backfires Explained
Winter is a great time of fun and adventure, and with it comes the joy of snowmobiling.
But with this joy also comes the risk of backfire – an irritating and potentially dangerous problem that can put a damper on your fun. It’s good to note that backfiring can be caused by a number of factors, including worn-out spark plugs, clogged fuel filters, or incorrect timing.
But whatever the case, the dreaded snowmobile backfire can be a real pain if you’re out on the slopes. Fortunately, there are a few simple, effective steps you can take to avoid and minimize the effects of snowmobile backfire, so you can get back to enjoying the winter wonderland.
In the next section, we’ll explore the causes of snowmobile backfire, how to fix the problem, and also provide some tips on how to prevent it from occurring in the future. So gear up for it, and let’s get started on learning how to tackle this common snowmobile problem head-on!
Air And Fuel Mixture
One of the most common reasons for snowmobile backfires is the unbalanced combination of gas and air. The combustion chamber won’t be functioning at its optimal abilities if there’s the mixture gets lean (more air) or rich (more gas), which could easily make the engine backfire.
The altitudes for a snowmobiling day can fall anywhere between 2000 and 3000 feet. But higher altitudes are associated with lower air pressure– the higher the altitude, the lower the air pressure. In other words, there will be less air available per square foot at higher altitudes.
The fuel supply from the carburetor won’t change; it will keep on delivering the same amount of gas while on the other hand, there won’t be as much oxygen to support the combustion taking place in the combustion chamber. Here’s a good way to explain this.
Imagine that you have started your snowboarding route at the base of a mountain, riding straight up the slope. In such case, your sled would start to bog down and the engine would respond slowly to throttle as you travel towards higher altitudes. The engine will be running excessively rich (too much fuel with less oxygen), which will cause the sled to backfire.
Fix: Readjust The Carburetor
In the carburetor, there are screws and jets that help determine what amount of air should go with what amount of gas. These jets, however, tend to lose their position and might require readjustments to work as expected.
The challenge with this fix is that it’s hard to do at home, especially if you’re not good at DIYs that involve fixing autos. Consider getting a mechanic to help do the necessary adjustments and resolve the air-fuel issue.
A perfectly adjusted carburetor will give a 1 to 12.5 ratio of gas to air with a 2-stroke engine. The air pressure will drop at higher altitudes. Therefore, the necessary adjustments should be done on the carburetor based on the air pressure, normally after about 2000 feet of altitude.
Internal combustion engines designed with EFI systems won’t necessitate any modifications to the air or fuel composition. This is because they have an ECM (electronic control module) connected to sensors, including those for air and gas.
The fuel ratio is automatically adjusted by this controller in accordance with the atmosphere. Otherwise, if that is not really your case, then you may want to get the carburetor readjusted, especially if your sled runs idle at more than 2000 RPMs.
The point here is simple; if you’re not using the right octane-level gas for your snowmobile engine, the fuel will definitely fail to ignite as expected, leaving the engine uncombusted and resulting in a backfire.
Most snowmobile owners prefer premium fuel mainly because they’re known to support the overall lifespan of the vehicles. However, premium fuel can resist detonation, which is not a good thing if the specific snowmobile engine isn’t designed for it.
Your gas could contain impurities like water, or it is old probably after staying in the fuel tank for a long time, which could result in residue forming in the gas tank. Note that if there’s water or residues in the fuel, and the gas reaches the combustion chamber, it will resist detonation, leaving some fuel unburned, and causing the engine to backfire.
Fix: Use The Right Octane-Level
The ideal fuel for most snowmobiles is 87 octane, which is what the majority of snowmobile manufactures recommend. Oher high-performance sleds will need 92 octane. Nonetheless, you can check the user manual of your machine to determine the right octane level for the engine.
Some snowmobiles come with a fuel filter ready in place, connecting the carburetor and the hose. In case yours doesn’t have any filter in place, you can always add one to prevent any impurities from reaching the engine.
Faulty Stator or Ignition Coil
The main purpose of the ignition coil is to boot the weak voltage from the battery or stator to deliver the high current that’s needed for ignition. As such, if the ignition coil fails to deliver the right amount of current, the fuel and air mixture in the combustion chamber will not ignite.
If the ignition fails the unburnt fuel or rather the mixture will exit through the engine’s exhaust pipe. The uncombusted fuel will then be burnt by the hot grills within the exhaust pipe, creating a loud sound, which is the backfire.
Fix: Checking and Replacing The Faulty Components
The major parts responsible for the primary current are the ignition coil and the starter. And they’re both related. That means if the starter on your sled isn’t functioning properly, there will be less current coming from the ignition coil.
Otherwise, if the ignition coil is okay, then the stator could be the culprit. You can easily check both the stator and ignition coil for problems by simply swapping them (one after the other with a new one).
The other approach involves using a digital multimeter to measure the resistance. Normally, the primary coil resistance should be between 0.2 and 0.6 ohms. The secondary coil should have a resistance between 18 and 21 ohms. Nonetheless, you can check for the correct resistance in the user manual of your machine.
In case the secondary coil is shorter or the resistance values do not really match whatever is suggested, then the best move would be to replace the stator.
Consider measuring the resistance on the ignition coil. The resistance values of the secondary and primary coils may differ slightly, but of course, you can determine the exact suggested values of these same by checking on the service/repair manual of the machine.
If you realize that the values are well off the manufacturer’s suggestions, then the best option is to get the faulty coil with a new good one.
Issues With Spark Plug
In the combustion chamber, combustion takes place when there’s a spark in the spark plug. This spark is responsible for igniting the air and fuel in the internal combustion engine. Thus, if the spark is too weak and not enough for ignition, then the ignition will not go as expected.
Instead, some mixture will go unburned, and will then cause the engine to backfire as it exists. The various problems associated with spark plugs include corrosion and faulty spark plug cables. Such issues could make the spark plug ignite a bit sooner or later than you’d expect.
Fix: Replacing The Spark Plug
Well, as mentioned, spark plugs often get corroded. The electrodes might also get consumed by the high current and spark occurring between them. As such, spark plugs have a lifespan and will call for a replacement after some time. So how do you replace the spark plug? You ask.
The first thing should be to locate the spark plug on your sled. You can find it under the hood, normally with some thick black wires running to it.
Once you’ve located the spark plug, proceed by removing the cap and then the spark plug itself. Be sure to use the right socket for these. The last thing you want is your machine reacting to additional problems. Remove the spark and check it closely.
If you see that the plug appears as if there’s some carbon on the electrodes or the space/gap between the electrodes is rather wide than expected, then you should have it replaced.
The best part about this fix is that it’s not as hard and the spark plugs are often cheap and readily available. To avoid backfires, it would be best if you checked the spark plug on your sled during every service and have it replaced if it’s not in good working order.
Also, the cap on the plug (which is usually made of a rubber-like substance with a thick wire running from the ignition coil) could have gotten loose, making the connection between the wire and the plug cap not as good.
You can fix it by unscrewing the plug cap and blowing it in to get rid of any dust or debris. If the terminals within the plug cap are rusted or old, consider replacing the cap altogether.
Then properly connect the wire and screw the spark plug cap on it. Screw the plug cap tightly until there’s a solid click sound.
Another thing is that if the insulation of the wire is damaged, then the wiring on your sled could short out. Wires tend to get frayed and rubbed between metal parts.
Unfortunately, this is not the easiest part so if you’re not well-versed with electrical stuff, you might want to just call a mechanic. Naked wires should be insulated with electrical tape and if the wire itself cannot be fixed, you should just replace it altogether. Fixing improper wiring will help prevent backfires and other problems associated with short circuits.
There’s also a chance that you removed the battery of your sled but didn’t tape the terminals as they should be. So check and make sure they’re well-taped.
Faulty Valves In Your Snowmobile Engine
This is not the most possible cause of snowmobile backfires, but it does happen. The intake and exhaustion of the cylinder are regulated by a valve. The intake valve opens, allowing the carburetor’s mixture of fuel and air to enter the cylinder.
After that, it closes and stays closed during combustion. When the combustion is over, the exhaust valve then opens, taking the exhaust fumes (resulting from the combustion) out of the cylinder. These valves must not be bent for the chamber to close. Otherwise, if the air and fuel mixture flows back to the intake or exhaust, it will result in a backfire.
Fix: Replacing The Valves
Again, this is a rare occurrence but it’s the worst of all other causes. Such backfires harm the engine more than anything else we’ve mentioned here.
Replacing the valves can be costly because you’ll need to take your sled to a repair shop, and the whole engine will have to be disassembled. It’s a technical task and not many people would be comfortable doing it. It calls for an experienced mechanic. After all, you don’t want to end up damaging anything else while changing the valves.
How To Prevent Snowmobile Backfire
There are a few things you can do to prevent your snowmobile from backfiring.
Maintenance comes first, of course. You should keep the machine well-maintained by doing routine inspections. You can find a list of check-up suggestions in the user manual.
Try to always keep the exhaust clean. All the undesirable effects associated with faulty combustion will be exacerbated by a dirty or blocked or clogged exhaust system.
Likewise, keep your catalytic converter in good shape. Otherwise, it can easily lead to backfiring if it gets compromised. Make sure your spark plugs are spotless and in good working order.
You should also check to see that the system has optimal airflow. If too much air reaches the fuel, the resultant imbalance will lead to backfires.
Ensure that the sensors and valves are operating properly and keep the overall part of your snowmobile clean. A healthy body makes a strong person and the same case applies to sleds.
Snowmobiling is a popular winter activity for many people, but one of the most annoying drawbacks is the backfire- the small flame and small explosion caused by various factors described above. Such problems are bound to occur during such winter activities, but on the bright side, you can use the tips above to reduce the backfire and make your snowmobile-riding experience more enjoyable.