Carbon fouled spark plug

Can spark plugs be fouled? Why does my spark plug keep fouling out? What fouls spark plugs? Carbon fouling is one of the potential fouling problems that happens to spark plugs.

According to NGK Spark Plugs, when the insulator nose of the spark plug is coated, it is considered fouled.

The website continues to explain that while carbon fouling can cause problems, if the spark plugs are cleane there should not be any problems afterward unless the spark plugs were also damaged. Carbon Fouling If the spark plugs have a matte black or grey appearance, it could be carbon fouling — something typically caused by a fuel mixture that is too rich.

During normal combustion, most of the fuel oxidizes and changes into carbon dioxide and carbon monoxide gas. Carbon collects on the plug electrodes because of incomplete combustion. The cause may be a simple one: You idle the machine more than you run it at full speed or the plug itself is designed to run.

If all of the spark plugs show heavy dry carbon fouling, the rich fuel mixture may be caused by too much fuel pressure (check for a defective fuel pressure regulator or a plugged fuel return line). A defective oxygen sensor that reads lean all the time can also make the fuel mixture run rich.

This video explains what happens if a spark plug becomes fouled, and the root causes for this.

If this carbon accumulates on the firing end of the plug, the insulator resistance between the center electrode and the metal shell will be reduced and this may cause misfiring. Here’s a quick list of the common spark plug faults: Ash deposits.

High-speed glazing. Insulator cracked or broken. Sometimes you can cure a problem — such as carbon-fouled plugs — by going to a hotter- or cooler-burning plug. You can identify these by the plug number: The higher the number, the hotter the plug.

Never go more than one step hotter or cooler at a time. I would look toward an ignition failure, given the carbon-fouled spark plug and misfire under load.

A faulty spark plug is not out of the question. A leaking fuel injector (although new) may also foul the spark plug. Just clean and regap the plug. Carbon-fouled plug: Black, dry, fluffy soot on insulator tip and electrodes.

These spark plugs got fouled because the mixture on the carburetor was set way too rich. Rich running engines have spark plugs that smell like gasoline. If the engine is running fine, then, nothing to worry about.

Probably lots of idling and slow running that have carbon deposited on the circumference area of the plug. Main thing is no oil, sign of overheating shown on used plugs.

The subsequent troubleshooting sections on spark plug fault diagnosis, are listed in alphabetical order. Black, dry soot on the electrodes and insulator tip indicates a carbon - fouled plug. Running the recommended spark plug. Also, have a fuel pump kit and new muffler on.

Soft, black, sooty deposits easily identify this plug condition. Check for a sticking choke, clogged air filter, or a carburettor problem - float level high, defective needle or seat, etc.

Years ago I thought a plug fouled was because of the carbon and lead build up. Since the lead is not in gas anymore does the plug foul because of to much fuel, being running to rich.

Or what happens when you run to cold of a plug. The plug fouls, why because the gas did not burn.