Full Answer
What is the spark plug gap on a Stihl Chainsaw?
In a Stihl chainsaw, the spark plug gap is normally 0.020. For other chainsaws, the gap varies. The most usual gap is 0.025. Let’s see how the spark plug gap ensures your Stihl chainsaw run, the problems with the gap, and all the details you need to know about a spark plug gap.
Why is my Stihl Chainsaw spark plug black?
Few other cases like black spark plug, rough idle, wet spark plug are also found. The wider gap causes the unwanted flame to the engine. And the gap may increase over time while you continue running your Stihl chainsaw for a long time. It is normal to face the problem with the spark plug.
Why won’t my Stihl Chainsaw start?
Your chainsaw engine will not start; sometimes, it results in cylinder misfiring. Few other cases like black spark plug, rough idle, wet spark plug are also found. The wider gap causes the unwanted flame to the engine. And the gap may increase over time while you continue running your Stihl chainsaw for a long time.
Why does my Chainsaw have spark plug gaps?
To ensure the combustion in your chainsaw engine, a spark plug is a key to igniting the air-fuel mixture inside the cylinder. While using the chainsaw, users face the problem with spark plug gaps frequently. Let us inform you that the gap between the electrode and periodic replacement is crucial for engine performance.
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What is the spark plug gap on a Stihl?
0.020"What is the correct spark plug gap for my STIHL trimmer, chainsaw, or blower? The correct gap setting is 0.020".
What is the recommended spark plug gap?
For most racing applications, you usually want the plug gap to be between 0.020 and 0.040 of an inch. Most engine builders seem to settle around 0.035 of an inch. Factors such as the type of ignition you run, cylinder heads, fuel and even timing can affect how much gap will work best for you.
Are all Stihl spark plugs the same?
Stihl Chainsaws use two different spark plugs depending on the chainsaw model. The NGK BPMR7A and the NGK CMR6H are the two spark plugs used in Stihl chainsaws.
How do I know if my Stihl spark plug is bad?
Signs of a Bad Spark Plug If the gas tank is full and the fuel is good but your small engine won't start, you probably have a faulty spark plug. If the fuel checks out and your engine starts but runs rough, a bad spark plug is likely the culprit.
What happens if your spark plug gap is too big?
If the spark plug gap in your vehicle is too big, the spark plugs will need a higher voltage to get the ignition spark to cross the gap. The engine can't always provide the extra voltage needed to cross the gap, so the spark is weaker and won't ignite your fuel mixture properly.
What happens if the spark plug gap is too small?
The customer may experience loss of power, misfires, spark plug fouling, increased plug wear, or poor gas mileage. Too small of a gap may give too weak of a spark to complete the combustion process within the engine; too wide of a gap can lead to the spark plug not firing correctly, causing misfires at high speeds.
What does a black spark plug mean in a chainsaw?
Thick black deposits indicate that the fuel/air mixture is too rich -- in other words, there isn't enough air in the mixture. A wide gap or corroded electrodes, on the other hand, are indications of a lean mixture. Oil on the plug indicates an oil leak.
What spark plug does a Stihl MS250 use?
BPM7A NGK Spark Plug Fits Stihl MS200T, MS210, MS230, MS240, MS250, MS260, MS270, MS280, MS290, MS341, MS361, MS390, MS441, MS460 Chainsaws. Fits most Stihl chainsaw models.
What spark plug does a Stihl bg56c take?
P SeekPro Spark Plug CMR6H for Stihl Blower BG56 BG66 BG86 BR200 BR500 BR550 BR600 BR600 SH56 SH86 Stihl PN 0000 400 7011.
How long are spark plugs good for?
A standard copper spark plug has an average life span of 10,000-20,000 miles. Silver plugs, used for older vehicles, can last up to 20,000 miles. Expensive iridium spark plugs or platinum spark plugs can last 60,000 miles. Extended life spark plugs or long life spark plugs can last 100,000 miles.
How do I know if my spark plugs need changing?
7 Signs You Need to Replace Your Spark PlugsThe car is hard to start. ... The engine misfires. ... You're heading to the gas station more often. ... The engine idling is rough and noisy. ... Your car struggles to accelerate. ... The engine is really loud during normal driving. ... Your 'check engine' light is on.
What causes spark plugs to go bad fast?
Oil in Combustion Chamber A leading cause of spark plug problems is a flow of engine oil into the combustion chamber. If oil leaks into the combustion chamber, it can cause the tip of the spark plug to get oily and dirty leading to premature failure.
Do NGK Spark plugs need to be gapped?
While most NGK spark plugs are pre-gapped, there are occasions when the gap requires adjustment. Care must be taken to avoid bending or breaking off the fine-wire electrodes. NGK recommends a round wire-style or pin gauge gap tool to measure the gap.
What is the proper gap?
0:012:56How to Gap a Spark Plug - YouTubeYouTubeStart of suggested clipEnd of suggested clipSo we're going to check the gap of each spark plug for this engine it suggests a gap of 0.05. SoMoreSo we're going to check the gap of each spark plug for this engine it suggests a gap of 0.05. So here's your little gap reader 0.05 is right there. So what you do and you want to be very careful
Does spark plug gap affect performance?
Spark plug gap is a main factor affecting the performance of the engine depending on the engine structure. According to specification of spark plug for several different engines, the size of this gap varies 0.9–1.8 mm. ... [Show full abstract] A narrow gap leads to weak spark to effectively ignite the fuel-air mixture.
Do spark plugs come pre-gapped?
Spark plugs traditionally leave the factory pre-gapped for their most popular application. However, a plug may fit hundreds of engines, from cars to golf carts. Gapping the plugs to your engine's specifications is important to prevent pre-ignition, detonation, fouling and poor fuel economy.
Does STIHL make a straight shaft trimmer that turns clockwise?
STIHL does not produce a straight shaft trimmer that turns clockwise. Only our curved shaft trimmers do.
How do I know if my STIHL trimmer will accept other cutting heads?
Please contact your authorized STIHL Dealer for special accessories that may be available for your trimmer.
Can I adjust my own carburetor?
This setting provides an optimum fuel-air mixture under most operating conditions. With most carburetors, it is only possible to adjust the engine idle speed within fine limits. Quite often adjusting the carburetor will not solve acceleration issues. To find the correct setting for your machine, please refer to your instruction manual. If you do not have a copy of your instruction manual, please go to our product manual webpage where you can download a PDF version.
Can I send my STIHL trimmer back to STIHL for repair?
STIHL Inc. does not accept product for repair or refurbishment. Please see your local authorized full-line servicing STIHL Dealer.
What is the minimum compression for my STIHL trimmer?
Generally the minimum is 110 lbs. of compression. However, this will vary by model. Compression readings alone are not enough to determine the condition of the engine. Compression gauges are not always accurate and different engines will provide different results.
Why does my STIHL trimmer flood?
The most common reason is due to too many attempts trying to start the machine in the choke position. When starting a STIHL trimmer unit, make sure to follow the starting instructions in your instruction manual. The manual provides the proper instruction for starting procedures, but there are many conditions that may affect how the unit starts. A good rule of thumb to follow is to remember that when placing the switch control to the full choke setting, more liquid fuel and less air flow into the combustion chamber in order to create a higher chance for ignition. Pulling the rope more than two to three times in this setting may flood the engine. The operator should move the Master Control Lever™ or choke lever from the full choke setting after three to four pulls even if the engine does not fire. Moving the lever to the next setting, the half choke or part throttle position, will allow more air into the combustion chamber and help resolve the flooding condition.
How to start a Stihl 89 octane trimmer?
When starting your STIHL trimmer make sure that you have fresh fuel mix of 89 octane or higher and never pull the starter more than 3 times in the choke position. If you have pulled more than that, more than likely it is flooded. Indications of flooding are the strong smell of gasoline or gasoline coming from the muffler. The best thing to do at this point is allow the trimmer to rest for 20 to 30 minutes then attempt starting again. Do not choke the unit, but leave the throttle lock on. If it still will not start, we recommend taking it to your local STIHL Dealer for evaluation.
What type of ignition system is used for spark plugs?
6) Type of Ignition system - magneto, CD (Capacitor Discharge), or Inductive. CD ignitions have very fast Voltage rise (short rise time) and therefore they also work very well with spark plugs that have high capacitance, such a spark plugs with multiple gaps and/or surface discharge spark plugs. On the other hand Inductive ignition systems generally provides longer spark duration...
What is the potential of an ignition system?
1) Potential of the ignition system - Spark Voltage (sometimes explained as Voltage potential or electrical pressure) corresponds with the distance that spark can cross at given air pressure and enviroment (concentration of the A/F (Air/Fuel) mixture etc... between the spark plug gap (center electrode and ground electrode).
What is the recommended spark plug gap for a lean A/F?
Generally the applications with low cylinder pressures (low compression ratio) running lean A/F (Air/Fuel) mixtures have large recommended gap (around .050"), and applications with high cylinder pressures (high compression, forced induction - turbo, supercharged, nitrous applications ,...) require spark plug gap smaller than .032". The dense A/F mixture is much harder for spark to penetrate, and require much higher voltage (pressure). Higher fuel concentration has the same effect (lower A/F ratio). That reason is why high power vehicles (1,000 horspower and more) often run a spark plug gap as small as .016". Some applications such as ProMod turbo cars using M1 fuel frequently run a spark plug gap as small as .012", even though they are equipped with some of the highest output ignition systems providing in excess of 60,000 Volts high current and high mJ power output.
What is spark plug gap?
For Champion spark plugs it is a little less logical and is as listed below: Spark plug gap is where spark plug spark discharge is designed to take place. On a conventional spark plug, it is the area between the center and the ground electrode.
Why is it important to set spark plug gap?
Spark Plug Gap setting is important for proper engine operation. To set the spark plug gap correctly, you need to use a spark plug gap tool. For reference, see our spark plug gap chart below, this chart converts metric measurements to standard.
Why are spark plugs so hard to fire?
Used spark plugs are hard to fire as the gaps are worn out, and insulation properties of the ceramic is compromised by solid combustion deposits and old fuel saturation. This robs available voltage at the spark plug gap, as it "leaks" through the low resistance carbon deposits to the ground, resulting in a weak spark.
How much power can you gain from spark plugs?
It is not uncommon to gain as much as 20 Hp just by replacing used spark plugs. Used spark plugs are hard to fire as the gaps are worn out, and insulation properties of the ceramic is compromised by solid combustion deposits and old fuel saturation. This robs available voltage at the spark plug gap, as it "leaks" through the low resistance carbon deposits to the ground, resulting in a weak spark. Think of a worn out spark plug gap like an old leaky water hose that requires more water pressure, and is like a restricting the flow at the end with your finger. More pressure is required form the leaky hose, because more water leaks out at other places than the hose end.
How does oil pull down?
As a general rule of physics, the oil will be pulled down by gravity once the chain stops turning, collecting at the bottom of the bar and seeping through the chain to puddle underneath the bar & chain assembly as well as under the drive sprocket.
How long can you keep fuel mix in a can?
First, make sure that you are using fresh fuel mix (never store or use fuel mix older than 60 days in can or fuel tank). Second, clean spark arrester screen in the muffler. Third, replace fuel filter in fuel tank. Fourth, clean or replace air filter.
What should be cleaned and inspected on a muffler?
The air filter, the cylinder fins, the spark plug and the dismantled cutting tool should be checked and cleaned (also see Instruction Manual). Metal parts should be lightly coated with oil to protect them from rust and corrosion. The spark arresting screen in the muffler should be cleaned or replaced with a new one.
Why does oil seep after being cut off?
The fact that it appears to be continuing to seep after the unit is cut off for several days is owed to the viscosity of the oil and the anti-flinging compound (lithium) mixed with the oil at the refinery. These factors give the oil a very thick consistency, which in turn explains a slower flow rate.
What causes a chainsaw to kick back?
Kickback occurs when the moving saw chain near the upper quadrant of the bar nose contacts a solid object or is pinched. The reaction of the cutting force of the chain causes a rotational force on the chainsaw in the direction opposite to the chain movement.
What fuel should I use for a Stihl chainsaw?
Note: STIHL recommends use of fuel with no more than 10% ethanol content. Using fuel with greater than 10% ethanol content may cause damage to your equipment and may void your STIHL warranty. Learn More…. My chainsaw will start and idle but won't run or stalls when I go to full throttle.
Where is the serial number on a motor?
Most serial numbers are stamped in the motor housing or crankcase to the left or right of the muffler looking down from the top on a flat surface. They will in most cases be 9 digits long and begin with the number 1, 2 or 5.