Soot buildup on one side of a spark plug typically indicates incomplete combustion, which can be caused by several factors, including an overly rich fuel mixture, improper air-fuel ratio, or oil leaking into the combustion chamber. Additionally, a malfunctioning fuel injector or a dirty air filter may contribute to uneven combustion, leading to soot accumulation on one side. Engine misfires or poor ignition timing can also exacerbate this issue. Regular maintenance and diagnostics can help identify and resolve the underlying causes.
Soot, or dry fouling of the plugs is a result of unburned fuel. The causes are (in order of likelihood) 1. Not enough air. 2. Weak Spark. Failed spark plug(s). 3. Too much petrol. 4. Ignition timing incorrect. The main thing to establish is the soot on all plugs or just one or a number. If all, then 1,2,3 & 4. If just one or two, or a bank if multi carbed, then focus on that bank.
probaly the air fuel mixtuer on the carb
either its running to lean or you have a bad exhaust valuve
lambo sensor - cat issues - over fueling - ht leads break in the vacuum system
Black soot isn't a good sign, one of ur plugs or plug wires must have burnt up. and should be replaced.
Dry Soot Buildup on Spark PlugsOften dry soot is an indication of an "over-rich" fuel mixture ratio.The first thing you ought to try is to take your vehicle into a professional automotive repair shop and have them do a computer analysis of the fuel delivery system [carburetor or injector system] and properly adjust the fuel mixture.
If the spark plug end (combustion chamber end) is coated with dry, black soot, it indicates weak spark or incomplete combustion. Note that this doesn't necessarily mean that the plug is bad; weak spark more often indicates a faulty coil or plug wire or, sometimes, an overfuelled cylinder.
burning oil
aerosols and soot from air polution
Check the air filter, fuel injectors, EGR valve and temperature sensor.
most likely, too much fuel.
It won't rev properly, and the spark plug might soot up.