If a spark is present, the spark plug is working properly. By "reading" the color of the plug you can tell a lot of things about how the engine is running. With the explanations above for its extremes, the spark plug is a good indicator for smaller settings issues which then become less obvious. The plug should be fairly clean. Cause: Lead additives in fuel. thanks. Check the spark plug and the ignition wire to be sure they are both properly functioning. In today’s cars, say Firestone Complete Auto Care technicians, if a plug starts to fail then the most obvious event should be the check engine light coming on or even flashing. The coil on that year should be able to make a bright blue spark at least a half of an inch long. It could have the tip missing or any of several other problems. Sometimes, a visible spark at the outlet is normal. The insulator is often tinted the color of charcoal. You can see the light brown color begin to appear on the left side of the insulator in the image below. When a vehicle engine is reluctant to start, it often means that the spark plugs need changing. Have someone crank the motor and hold it close to the block. Plus, using a spark tester is safer than grounding a plug. In this article, we’re just going to discuss heat range. Conversely, a cold spark plug has a shorter insulator nose and absorbs more combustion chamber heat. A light tan/gray color tells you that the spark plug is operating at optimum temperature and that the engine is in good condition. Save Share. Black is the color … For many racing engines, spark plug color is a window into the engine combustion process that can be used for tuning. You can't be serious. When I check the spark plug spark (with a spark tester) I get a good white spark on all plugs. I replaced my plugs with ngk about 1000 miles ago on my 2000 heritage, they still look brand new. 46 Posts . i took out the spark plug and checked out the color of the spark because my bike is hard to start and i heard that blue spark is good and yellow is bad well mine is yellow and i think it is because i put low octain gas in the first time riding . Contact us and we’ll send over an electrician who can diagnose and fix the problem ASAP. In order to perform the check we should follow the following steps: Ride the scooter warm. Re: What color should the spark be on the NGK Iridium Spark plugs I hate to disagree but a weak yellow spark is not very good and in most ignition systems means trouble. Plug colors tell the mechanic how the engine is running and can be very important. Spark Plug Tuning - Light My Fire The Tiny Spark Plug Should Be A Big Tool When It Comes To Tuning Your Race Engine. The spark plug is vital to the engine running and any problems with it could cause a multitude of engine difficulties. As the gap between these two points grows, the voltage required to bridge the gap increases proportionately. Place the original spark plug back in, and set the spark plug wire against the motor. DH Spark Plug off rear cylinder with 500 miles with AC, FP fishtails and dealer flashes. Look at the spark plug porcelin for the color and condition of it. So you should check your plug often. Because the spark plug is inside the engine and is the only easily removable part it can be used as an indicator to the state of tune and condition of the engine. Normal spark plug color. Exposure to heat and combustion byproducts changes the colors on the various parts of the spark plug. You think your gas quality has to do with the color of the spark. ... which can have a greenish color. A common malfunction is a wet spark plug. A plug that has racked up miles should have a brownish or grayish color on the insulator and electrodes, but some gas additives have been known to turn fresh insulators blue, pink or purple. Appearance - Firing tip is damp with gasoline, usually the odor of fuel is present on the spark plug. The black spots (look like pepper sprinkled on the plug) indicate a little too much heat on the plug which causes detonation by having the heated plug fire off the mixture prior to the spark firing. The coil voltage measures about 100 volts and should be 130 volts. Pull the rope to spin the flywheel and watch for a spark on the original spark plug. Spark plugs usually require voltage in excess of 20,000 volts to 'fire' properly. 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. Because of this, the tool provides an accurate measurement of whether there’s enough spark to jump the plug gap. In reality, a spark happens every time you plug an … Dry: Black Soot Buildup . I hear the spark should be a blue color. The first is obvious, to create the spark necessary to ignite the air/fuel mixture in the cylinder. A spark, big or small, could cause an electrical fire. Use a Coil-on-Plug (COP) Probe Any resistance at all would mean the plug is bad. This is why spark plug manufacturers Champion Aerospace and Unison Industries recommend that spark plugs be serviced every 100 hours. Unfortunately, there is no single answer to this question. Is this OK?? Normal spark plug color should show a light tan on the insulator tip. k This is often caused by over advanced ignition, timing, poor engine cooling system efficiency (scale, stoppages, low level), a very lean air/fuel mixture, or a leaking intake manifold. Step 7 Rewind the rope around the flywheel and turn the lawn mower's ignition switch on. New spark plugs should be able to fully burn all of the air and fuel mixture in the engine cylinder and little to no carbon buildup should continue to occur. A clean, white insulator firing tip and/or excessive electrode erosion indicates this spark plug condition. Generally accepted normal condition for a used plug in a properly operating engine is a light ash or gray color on the ground electrode, center wire and end of the plug. You may be able to see this arcing on a dark night with the engine running. How often should I replace my spark plugs? A hot spark plug maintains a higher internal operating temperature to burn off oil and carbon deposits, and has no relationship to spark quality or intensity. For a two-stroke engine, having a fresh spark plug is incredibly important. The top of a new spark plug is covered in white ceramic insulation. The color should be read by looking at the porcelin insulator and compared to the plugs shown on the next few slides. Without knowing your system inside and out, however, tuning with spark plug color alone can be misleading. If you have electronic ignition, a hotter spark is produced that will jump through old spark plug wires. Remove the spark plug and use a wire brush to completely clean the spark plug. Spark Plug Wires-- Make sure the spark plug wires are not shorting out. I've never seen an orange spark usually, white or blue color. Spark plugs have 2 jobs. This condition is ideal, the spark plug and engine air/fuel mixture are operating properly. You'll hear an electric snap or crack at the same time. A yellowish color is typically caused by leaded gas. Single Fire - Single Plug: .035 to .040 Single Fire - Dual Plug: .022 to .025 Dual Fire - Single Plug: .035 to .040 Dual Fire - Dual Plug: .035 to .040 - When wired so each coil fires a plug … These usually look WET and smell of gasoline. 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. If none of this works, you should call your local small engines repair shop to have it … If you replace your spark plugs and they are black and wet again in little to no time it may not be your spark plugs that are the actual issue. Red is a sign of iron particle s or rust in the fuel system. Like right out of the box, I'm I lean or will it take awhile to get color on them . Check for faulty or sticking choke, overly rich fuel mixture, ignition problems, leaking fuel injectors, or spark plug heat range is too cold. Grey to Light Golden-Brown Color . Worn spark plugs or spark plug wires can trigger your check engine light to come on. Being able to “read” a spark plug can be a valuable tuning aid. Lean spark plug color. The sparkplug also says if you need to change anything in the mechanics. Discussion Starter • #1 • Jun 17, 2016. Fundamentally, there are two types of spark plugs. 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. The voltage at the coils are low. Is it possible with the gas we have now days to get color (light brown) on the spark plug. A quality spark tester, on the other hand, requires tens of thousands of volts to fire. A good spark plug should show an open circuit between the center electrode and the tip. Low Compression-- (See our discussion of engine diagnostics for a compression test procedure.) All voltages before the ignitions coils are good. Spark plugs in general are always a controversial topic – copper vs iridium, hotter vs colder, single or multiple electrodes, brand vs brand and plenty more. A bright blue is your most desireable and is usually a sign of a healthy ignition system. This means the plug has a higher internal temperature, and is said to be a hot plug. By examining the insulator firing nose color, an experienced engine tuner can determine a great deal about the engine’s overall operating condition. Ignition system problems causing a weak or intermittent spark. Air/fuel mixture is too rich, the carburetor settings are incorrect. See if you get a spark from the spark plug. Spark plug heat range is too cold for the operating conditions. Pull a spark plug and then reconnect it to the spark plug cable. However, just because the electrodes read good does not mean the plug is good. This creates two flame fronts that collide and can cause great amounts of damage. A lean spark plug will have little to no color on the insulator tip. Like many automotive components, spark plugs don't last forever. As spark plugs grow older, they lose their sharp edges as material from the center and ground electrodes is slowly eroded away. 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