Stihl Outdoor Power Equipment Spark Plug Fouled Wet: How to Fix It

Q: Why does my Stihl spark plug keep getting wet and fouled?

Repeated spark plug fouling is usually caused by a consistently rich fuel mixture due to a dirty air filter, incorrect carburetor adjustment, old fuel, or a faulty ignition system that isn't burning fuel completely.

Q: Can I clean a fouled wet spark plug or do I need to replace it?

You can often clean a wet fouled spark plug with a wire brush and allow it to dry completely. However, if the plug fouls repeatedly or the electrode is damaged, replacement is recommended.

Q: How do I prevent my Stihl equipment spark plug from fouling?

Use fresh, properly mixed fuel, keep the air filter clean, avoid extended idling, and ensure the carburetor is properly adjusted. Regular maintenance prevents most spark plug fouling issues.

Q: What's the difference between wet fouling and dry fouling on a spark plug?

Wet fouling appears as fuel-soaked deposits and indicates too much fuel reaching the combustion chamber. Dry fouling shows as dry, sooty deposits and typically indicates oil contamination or incorrect heat range.

Abstract

A fouled wet spark plug in your Stihl outdoor power equipment indicates an overly rich fuel mixture or ignition failure that's preventing proper combustion. This condition floods the spark plug with unburned fuel, making it impossible to create the spark needed to start your engine.