Too hot a spark plug, low octane fuel, lean airfuel mixture. The color should be read by looking at the porcelin insulator and compared to the plugs shown on the next few slides. Nice, greybrown deposits, lightly coated core nose. A healthy spark plug will have a little bit of electrode erosion but no abnormal deposits while the color would be a light tan, gray, or brownish. If your motorcycle does not seem to be running right, take a look at the spark plugs. Ive check the cylinders when i had the im off and found no further redbrown anywhere in the engine. If the engine is running to lean, the spark plug can look greyish white. Put new ngk plugs in last night and did an oil change, but the exhaust just wreaks of co which is the test i failed at idle. If you notice any black, dry soot on the spark plug, this is a sign of carbon fouling, which means your engine has been running too rich, and. This leaves high molecular weight fractions of fuel that will not burn, but eventually deposit condenstate on the in. If your engine is running too lean, the spark plug will be white. This is how your plugs should look after theyve been used for a few miles. A lean spark plug will have little to no color on the insulator tip.
You can actually read your spark plugs for valuable clues about how your engine is operating. Check out the images below, courtesy of ngk spark plugs, and get ready to do a little light reading the next time you pull your spark plugs. A motorcycle running lean will have little or no wear on the spark plug because its not igniting near as much fuel as it should be. If you notice any black, dry soot on the spark plug, this is a sign of carbon fouling, which means your engine has been running too rich, and you should visit a mechanic to figure out the cause. This plug eventually fouled and the bike would not start. Plugs change colors and the different colors can explain such things as if the engine is running too hot or if the engine is worn. Learning how to read a spark plug is quick and easy, and can equip you with the skills to determine when to change out your spark plugs for optimal performance in short, the reading of a spark plug involves evaluating the condition and color of the tip of the spark plug. Whenever you are rejetting or tuning your carburetors. The heat range numbering system used by spark plug manufacturers is not universal.
Was wondering if changing the spark plug gap could be the reason. The worlds largest oe oxygen sensor manufacturer now offers a full line of premium technical sensors for the aftermarket, featuring more than 6,800 skus. Causes can include the engine overheating, incorrect spark plug heat range, a loose spark plug, incorrect ignition timing or too lean of an airfuel mixture. This guide was designed to assist the technician, hobbyist, or race mechanic in understanding, using, and troubleshooting spark plugs. Is your spark plug black, wet, greasy or dry, dusty or covered in soot, white and crusty or speckled with crystals, i will show you how to read your spark plug and show you what is normal. By reading the color of the plug you can tell a lot of things about how the engine is running. The image below shows a plug off a motorcycle that was running pig rich. If its fuel injected, reading plugs is not an accurate way of determining whether or nor the engine is running lean unless you do a full throttle run, then immediately shut down the engine and check the plugs. Normal spark plug color combustion deposits are slight and not heavy enough to cause any detrimental effect on engine performance. The plugs on the left would be ok for a 4stroke, but in a 2stroke they are lean, hot, and dangerous. The plugs on the right would probably indicate imminent failure for a 2stroke. A normal spark plug will have brown or grayishtan deposits on the side electrode. Dont look at plugs youve been running on the muffs. Understand how to read the spark plug color car from japan.
My old oem spark plugs also dilkr8b6 have become noticeably worn at about 64k km. Just the mere spark plug color can determine the condition of the bike. Be aware that the use of 100ll will turn all these readings to a greyer color, but general appearance will still be similar. The porcelain is the insulator between the center electrode and the spark plug housing. A few tips on what the different colorations mean would be good too. Why are my spark plugs white and i have oil leaking out of their sockets. Plugs are ideally suited to engine, engine probably in good.
This is the most accurate way to see how the plugs and fuel mixture are when running. If your plugs indicate that something is seriously wrong with your engine, ask a professional for an opinion. After a test run, the spark plug can be examined with the naked eye or under a magnifying glass for minute particles, cracking, or surface bubbling. If your spark plug has started to look white in colour, this indicates that something is making the plug run too hot. Plug colors tell the mechanic how the engine is running and can be very important. Spark plug pictures for lean to rich running engines this section provides a visual representation of how the spark plug can look depending on how the engine is running. If your spark plugs look good, problems with your ignition system can also preventing a spark. I am checking my spark plugs to see how my engine is running. I was wondering real quick if the spark plug gap will change the air fuel mixture. But on an automotive engine with a higher compresssion ratio and under. The pipes should be a medium to dark gray or tan color. Check for correct application of spark plug heat range too hot, wrong spark plug for engine, cross firing of ignition cables, over advanced timing, lean fuel mixture, defective egr valve, accumulation of combustion chamber deposits, hot spots in the combustion chamber due to poor heat dissipation, improper installation torque applied to spark plug, andor head gasket protrusion into the combustion chamber. So, you may well understand the importance of this device in keeping the engine running. I recently just set the correct gap on my spark plugs, and now the bike is running rich.
How to read spark plugs to diagnose engine troubles. How to diagnose and read the color of your spark plug. Spark plugs and what they say from engineering of cixi. If your plug is grey or white, than you know that your engine is running too lean and. In regards to dialing in my jetting, what do these pictures of this spark plug tell you. How to assess trouble by checking your spark plugs dummies. Upon examining the old plugs, they appear to have held up well under the rich tune 14 afr and there is no damage after occasional running lean for a few weeks because of a faulty fuel pump relay. Spark plugs are one of the most misunderstood components of an engine. Your automobile keeps moving on the road because of the constant ignition.
This glazing of the porcelain actually becomes a conductor and the spark will jump from the electrode to the porcelain resulting is a very weak small if any spark. Recordrunning sprint car engine temperatures are typically run at 220f cooling system temperature. So i know that if the jetting is correct the plug should be a tan color, black rich and white lean, but i pulled the plug on my yz250f and seeing a black ring around the edges and some of electrode, but it looks white on the tip of the electrode. Reading spark plugs, what everyone should know about sparkplug reading. How to tell if a motorcycle is running lean and how to. Why are my spark plugs white and i have oil leaking out of. For example, a 10 heat range in ngk is not the same as a 10 heat range in champion nor the same in autolite. Even just by staring at it, you can already grasp the message. Im still really bad at telling what color my spark plug should look like, any thoughts on if this is a good color or if its to dark. The top of a new spark plug is covered in white ceramic insulation. Important technical articlejetting and tuning weber.
If the engine is running too rich the spark plug will look black, sometimes a glossy black if its really rich. Replace with the equivalent autolite spark plug at the proper interval. A low compression engine running at a steady state with a constant fuel supply wont quench even a spark plug with a yellow spark. However, your spark plugs will become either too clean evidenced by a lack of normal color or white when your engine is running significantly lean. Checked the valves last night and they were very close to spec, the real issue is the thing failed smog, is running rich, i cant get it registered because of the smog issue and i dont know jack about setting a carb. These can range from a faulty spark plug lead, shorted kill switch or flywheel key damage.
You need to check if there is any problem in the cooling of your engine, or there is any scope for lean fuel mixture or incorrect. Spark color to determine ingition coil performance. When new spark plugs are installed, replace with plugs of the same heat range. And, too high compression, or insufficient engine cooling. If the spark plug is black and oily, they are oil fouled. To read a spark plug, start by checking the color, since an undamaged spark plug will be light grey, or possibly tan. Spark plug pictures for lean to rich running engines. Symptoms of running lean are overheating, bogging or loss of power, and delay of returning to idle from higher rpm s. Heres another person saying spark color doesnt matter. A light tangray or brownish color, along with very little electrode erosion, indicates optimal operation conditions, including a healthy engine and correct spark plug heat range. Conversely, if the insulators white and flaky then your engine is running too lean. Numerous questions have surfaced over the years, leaving many people confused.
A common symptom of your car running lean is that your spark plugs are clean or turn white. If your engine is running perfectly, then this part of the plug would soon become a tan color. If they are black then you are too rich, if they are light gray or white then you are too lean. To read a spark plug and assess engine troubles, you first have to remove it. If the ground strap is showing a good color line but the porcelain is showing no color at the base then your plug may be too hot, drop down a range. Like the mechanical version of the magic 8ball, your spark plugs may have the answers for you. Efi mustangs tend to run lean and have white plugs at idle and part throttle cruise to get the engine warm quicker, to reduce fuel usage.
Is there an issue with oil control or ignition timing. This means that the spark must jump the 716 gap and the spark plug gap in the motor while running. Spark plugs change color and that change goes along with its. Either way, youll need to tune your carb to adjust the fuelair mixture. Spark plugs can provide valuable information about your vehicles performance and can predict potential problems. Go out and run the engine in the water under the condition rpm youre investigating and kill the engine as quickly as practical and then pull the plugs. Brown to grayishtan color and slight electrode wear.
If the plug is wet and oily, there are a couple of possibilities. You can then also increase engine rpm to verify spark at higher speeds. Spark plugs are generally a brown or grey color, which is caused by normal ignition. You need to check your spark plugs to see if you running rich or lean. Correct heat range for engine and operating conditions.
This is my 3rd set of spark plugs ngk, bosch and densos. Conversely, lean spark plug indications from excess engine heat can actually be made with a rich alcohol fuel mixture. Remove the spark plug and examine the insulator the porcelain color. Black sparks indicate that the temperature of the combustion chamber is too low. If the engine is running too lean, the spark plug can look greyish white. You will usually see splotchy deposits on the plugs after the run, either green or yellow in color and of course the tell tale shiny glaze. If your showing good color on the porcelain but the ground strap fails to show an indicator then your plug is too cold, go up 1 heat range. Ive been running with the through the hood ram air for a while and have noticed that ever since i have my spark plugs have come out redbrown in color. Spark plug color evidence of what is happening inside. Listen closely because your spark plugs may be trying to tell you something. Blisters on the insulator tip, melted electrodes, or white deposits are signs of a burned spark plug that is running too hot.
With a full line of spark plugs, coils, and wire sets, ngk covers 95% of import and domestic vehicles on the market. How to fix the issue of running lean when a motorcycle runs leans, the likely culprit is the fuel delivery system. Furthermore, indicating the plug is in the correct heat range and has been operating in. I dont believe you get a good idea of whats going on in an unloaded condition.
Note the brown to greyish tan color, and minimal amount of electrode erosion. Look at the spark plug porcelin for the color and condition of it. And if you are running with the choke on, something is wrong. I checked the colour of the spark plugs and knew it was running a bit. If everything is very white with glazed deposits on the insulator tip, a too lean fuel mixture is likely or the spark plug is too hot for the engine, or at least for the conditions for which it was used. What color should the spark be when using a spark tester.
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