Notice the color of the porcelain insulator that is around the center electrode and also the color of the ground strap. You can use the burn color of your plugs and reference the plug color charts below to determine if your engine is running rich or lean. 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. I recently just set the correct gap on my spark plugs, and now the bike is running rich. Spark plugs fact and fiction car craft magazine hot rod. Spark plug porcelain tan half way around and white the other. Replace with the correct heat range of autolite spark plug. Reading the spark plug jet more by feel more than plug color on a two stroke. Various color indications on a spark plug after one drag racing test run using 6percent nitro. To read a spark plug and assess engine troubles, you first have to remove it. Nov 03, 2017 how do you read a motorcycle spark plug.
This leaves high molecular weight fractions of fuel that will not burn, but eventually deposit condenstate on the in. Home about us contact us technical corporate code of conduct pdf. Lets say you pull your plug and check color, you find it is a bit brown because you a little rich. A symptom of running rich is black smoke exiting from the exhaust. Hi daniel, i had a shitty spark plug on my polini sport, equivalent with the ngk b9es, the color of the spark plug was chocolate brown. A white or real light plug color could possibly mean the carbs is too lean. A motorcycle running lean will have little or no wear on the spark plug. Also, if the pcv valve is plugged or inoperative it can cause a buildup of crankcase pressure. The ignition timing can be checked by looking at the color of the plug. This causes a misfire, a loss of power and fuel economy, and an increase in tailpipe hydrocarbon hc emissions.
Instead, they melt to form a conductive coating and misfire will occur. Lots of other things are more likely to cause preignition or knock. I am starting the troubleshooting by looking at the ignition system. Your engine runs lean if your airtofuel mixture is too light this. This condition indicates that spark plug temperatures have risen suddenly during a hard, fast acceleration period. Hold the light and its magnifier close to the plug. If everything is good, the spark plug should have a tanlight brown color. This condition is ideal, the spark plug and engine airfuel mixture are operating properly. Oct 20, 2014 page 1 of 2 spark plug colour running lean.
It is hard to distinguish a plug with a too hot heat range from one running lean, but these are not hot plugs and they are not running lean. Compare that with the plugs you removed from your engine. What color should the spark be when using a spark tester. So, you may well understand the importance of this device in keeping the engine running. Hey guys, i was pulling a p0306 code misfire on cylinder 6, so i replaced my plugs, wires, distributor cap and rotor. Check plug temperature value, ignition timing, fuel octane rating might be too low and mixture setting too lean. Two strokes make the best power at low engine temperatures and that combined with oil in the fuel and cold heat range spark plugs makes for a good plug reading that is darker than most would expect to see. Check your owners manual to ensure that you have the correct spark plug for. How to check your spark plug for the correct carburetor setting. Btw, the iridium spark plug will ensure better performance than standard spark plugs.
Symptoms of running lean are overheating, bogging or loss of power, and delay. We recommend spark plug replacement at oe specified intervals or sooner if spark plug problems are suspected. How to read spark plugs to diagnose engine troubles. Adjusting your carbs for performance in different throttle positions if you remember what throttle position each component of the carb control, you can begin to make some adjustments depending on the running conditions you experience.
Over time, the spark plugs in a healthy engine develop a slight brown or tan tint of color on the center and ground electrodes. Once you get the socket over the spark plug, place your hand over the head of the wrench, grasping the head firmly and pull the handle, hitting it gently with the palm of your hand to get it going. 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. As the gap or pressure is increased the snapping blue spark will. How to tell if a motorcycle is running lean and how to fix it.
Part number 276s may be used for header applications in place of pn 276. Even a couple of minutes can change a clean plug to sooty. However, your spark plugs will become either too clean evidenced by a lack of normal color or white when your engine is running. Assuming no foreign particles have made their way into the motor, other causes include an undertightened spark plug or insufficient octane rating of the gasoline used. When i get home and start tearing down my bike i decide the check my spark plug. The image below shows a plug off a motorcycle that was running pig rich. Too hot a plug can mimic lean mixture, a cold plug can appear as a rich mixture.
I am checking my spark plugs to see how my engine is running. Spark plug reading can be complex and sometimes frustrating. Spark plug color is only accurate when checked after a high speed run, engine turned off at max rpm, and craft glided in with engine still off. When a spark plug becomes fouled for any reason, the spark plug will fail to fire and ignite the airfuel mixture. In general, a light tangray color tells you that the spark plug is operating at optimum temperature. Wornout spark plug preignition fuel additives ash deposits. Too little indicates lean jetting while excessive build.
To read a spark plug, start by checking the color, since an undamaged spark plug will be light grey, or possibly tan. Again, look in your owners manual or online about how to clean your specific carburetor. Running proper timing also reduces exhaust valve temp which is another. As the gap or pressure is increased the snapping blue spark will win. Spark plug color evidence of what is happening inside. Airfuel mixture is too rich, the carburetor settings are incorrect. If the firing end of a spark plug is brown or light gray, the condition can be judged to be good and the spark plug is functioning optimally. If the engine is running to rich the spark plug will look black, sometimes a glossy black if its really rich. Feb 16, 2011 dont beat yourself up trying to get a perfectly and evenly colored plug, just make sure that the color that it is is a good color. Mar 29, 2019 to read a spark plug, start by checking the color, since an undamaged spark plug will be light grey, or possibly tan. Spark plugs wear down over time, but how they wear can tell you a lot about your engine and how its performing. The special spark plug is screwed into the spark plug hole in place of a normal plug. The white porcelain is showing a lean condition at wot, its not too far advanced as the total timing mark or color change is right in the apex of the ground strap curve.
Spark plug heat range is too cold and or caused by extensive lowspeed, short distance driving. Jul 27, 2014 hi daniel, i had a shitty spark plug on my polini sport, equivalent with the ngk b9es, the color of the spark plug was chocolate brown. Reading spark plugs is a technique used by auto mechanics to diagnose conditions within an engine. Spark plug how do i read my spark plug condition what. Spark plug colours and engine problem guide download this sheet as a pdf file here a spark plug is an electrical device that fits into the cylinder head of some internal combustion engines and ignites compressed petrol by means of an electric spark. For the average stocker in good running condition, spark plug selection is a cinch choose whatever brand s on sale, look up the plug part number in. Replace with a colder heat range of autolite spark plug. A spark plug can become damaged for several reasons, most often because of an extremely lean condition or because the spark plug is too hot for the motor. An examination, or reading of the characteristic colors and markings on the firing end of the spark plug can indicate conditions within the running engine. Spark plugs have an insulated centre electrode which is connected by a heavily insulated wire. Now, ive got a ngk br9eix iridium spark plug, and looks like its running too lean wtf. If your spark plug is white in color or appears blistered, that means something is making the plug run too hot. Dec 11, 20 if you want to test if its spark or fuel just pull the spark plugs, replace them, but put a small squirt of fresh straight gas into the spark plug hole before installing the new plugs. Car seems to go pretty well, but i feel its a bit underpowered compared to my other mini which is a 1995 spi cooper currently half welded in my garage.
I was wondering real quick if the spark plug gap will change the air fuel mixture. Your automobile keeps moving on the road because of the constant ignition. How to assess trouble by checking your spark plugs dummies. Was wondering if changing the spark plug gap could be the reason. If the engine is running to lean, the spark plug can look greyish white. How to check your spark plug for the correct carburetor.
Be aware that the use of 100ll will turn all these readings to a greyer color, but general appearance will still be similar. You lean it out some and run a few tanks through it but when you check again it is the same color. Since improper heat range can easily cause detonation and spark plug insulator failure lets take a look at that. Replace spark plugs and crank engine slowly to distribute oil. A spark plug is an electrical device that fits into the cylinder head of some internal combustion engines and ignites compressed petrol by means of an electric spark.
As the spark plug can be removed for inspection, the effects of combustion on the plug can be examined. It is right inside the combustion chamber and more importantly can be removed for inspection. Apr 16, 2017 check to make sure the plugs are tight but do not overtighten them. If the car has been running rich due to lots of idling or incorrect fuel mixture then it is possible to glaze the plugs and short them out during a run because of the sudden heating of the plug with the soot on the porcelain. Blisters on the insulator tip, melted electrodes, or white deposits are signs of a burned spark plug that is running too hot. Heres a guide on how to detect issues by the color of deposits found on your spark plug. Spark plug colours and engine problem guide download this sheet as a pdf file here. Dry and wet fouling although there are many different cases, if the insulation resistance between the center electrode and the shell is over 10 ohms, the engine can be started normally. Spark plug fouling is a common cause of engine misfire. It means that the engine is running lean, which will result in the engine running too hot and can cause serious engine damage even seizure. Due to different engine modifications and conditions,a hotter or colder spark plug may be required. Oil may also be pulled into the chamber because of excessive clearance in the valve stem guides.
Correct heat range for engine and operating conditions. Dec 20, 2012 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. Check the owners service manual to determine the exact location of the spark plugs. The electrode strap shows color all the way to the weld, indicating high combustion temperatures.
Feb 23, 2018 your automobile keeps moving on the road because of the constant ignition. A clean, white insulator firing tip andor excessive electrode erosion indicates this spark plug condition. Two strokes make the best power at low engine temperatures and that combined with oil in the fuel and cold heat range spark plugs makes for a good plug reading that is. Spark plugs can provide valuable information about your vehicles performance and can predict potential problems. Check for faulty or sticking choke, overly rich fuel mixture, ignition problems, leaking fuel injectors, or spark plug heat range is too cold. Prefix sign denotes new part numbers available 1196. Caused by piston rings or cylinder walls that are badly worn. Symptoms of running lean are overheating, bogging or loss of power, and delay of returning to idle from higher rpms. Jul 24, 2018 how to diagnose and read the color of your spark plug video duration. The goal is to get a good dark coffee brown color on the spark plug, which represents the correct. An examination, or reading of the characteristic markings on the firing end of the spark plug can. Brown or grayish tan deposit on side electrode, everythings fine.
Spark plug heat range is too cold for the operating conditions. Jet more by feel more than plug color on a two stroke. 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. Before inspecting plugs that have been run in your motor, familiarize yourself with a new spark plug first. Replace spark plug s and crank engine slowly to distribute oil. A light tangray or brownish color, along with very little. Under a magnifying glass not necessarily visible to the naked eye, the porcelain shows a crack at the 6. A good spark plug tester will pressurize its test cylinder to the same pressure as engine combustion chamber. Use a colder plug to lean it out, a hotter plug to richen it. The spark plug tip will bear witness to what is happening inside the engine. Sometimes happens briefly during running in period. Understand how to read the spark plug color car from japan.
Spark plugs are generally a brown or grey color, which is caused by normal ignition. Anything and everything you want to know about spark plugs. A lean spark plug will have little to no color on the insulator tip. Brown to grayishtan color and slight electrode wear.
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. Spark plugs are one of the most misunderstood components of an engine. Apr 03, 2010 iso, the color of the sparkplug is an indicator of how effeceint combustion is in the engine, too light like it is indicates being lean. I just read the tuning link that you shared with us and i agree with most everything said except the color of the spark plug.
Spark plugs initiate combustion in internal combustion engines. Lean airfuel mixtures cause plug tip and cylinder temperature to increase, resulting in. As a result, normal combustion deposits do not have an opportunity to fluffoff as they normally do. 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. A melted electrode on your spark plugs means that theyve been running too hot for too long and could burn a hole through the top of a. With the engine running, you can then view whats going on in the combustion chamber. Heres what fouled spark plugs look like running too rich. 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.
How to diagnose and read the color of your spark plug. Lean airfuel mixtures cause plug tip and cylinder temperature to increase, resulting in preignition, detonation, and possibly serious spark plug and engine damage it is important to read spark plugs many times during the tuning process to achieve the optimum air fuel mixture. Appearance firing tip is damp with gasoline, usually the odor of fuel is present on the spark plug. What a spark plug can you about your engines condition. The electrode wear is uniform and like the threads, should appear free of oil and unburned carbon. Spark plug pictures for lean to rich running engines. I noticed that the ground arm on the plug was kinda white. If it fires for a second or two the spark is fine and you know the carbs and possibly a fuel pump is not delivering gas. Ignition system problems causing a weak or intermittent spark. As the rings seat in and power improves the fuel requirements will change. 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.
The insulator is often tinted the color of charcoal. They often come with specific instructions on how to remove the spark plug as well as. Im still getting the misfire code, plus now theres a clicking sound coming from the 246 side of the engine, and a p0174 code bank 2 running lean. When they say a tan color is ideal, that is in reference to a 4stroke engine or a. Tuning the engine with a colortune plug how a car works. Plug heat range can have a large effect on this process. Use of various brands of synthetic oil will sometimes add extraneous colors to the ceramic portion of the spark plug, which can make things more interesting. If your engine is running too rich, the spark plug will be black and sooty. Therefore, since the spark plug is the initiating factor in this mysterious combustion process it is imperative that we understand, 1. Black sparks indicate that the temperature of the combustion chamber is too low. The plug is showing me by the deposits on the tip of the electrode and also the deposits right on the edge of the threaded body. 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. With help from the spark plug experts at ngk, well teach you how to diagnose minor tuning issues or potentially major engine problems by examining your spark plugs. All resistance values through the ignition system are per spec.
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. For a given spark gap test an yellow spark against a blue spark. So took it for a desert run up to randsburg right next to red mountain here in southern cali. If the fuelair mixture is a deep blue colour, then the mixture is correct. Check for problems in your engines cooling, a lean fuel mixture or incorrect ignition timing. If your spark plugs are fouled or damaged, it can lead to a host of problems including. A common symptom of your car running lean is that your spark plugs are clean or turn white. It is hard to see all the plug with the wrench handle in the way, but from what you can see they look ok.
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