Why is White / Blue Smoke Coming from the Engine?

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What could be causing the white/blue smoke from the engine?

Blue or white smoke coming from your engine usually indicates burning oil, which can be caused by:

  • Overfilling the crankcase with oil

  • Incorrect oil grades

  • Operating engine at greater than a 15 degree angle

  • Inoperative crankcase breather

  • Crankcase air leak

  • Blown head gasket

  • Worn cylinder and/or rings

  • Turning/tilting the engine on its side for storage, oil change or any other reason

Note: If the engine has to be tilted, ensure that either the spark plug is facing upwards or the muffler side is facing downwards to help prevent oil from escaping the crankcase.


Other reasons for blue or white smoke from engines include:

  • Exceeding the engine’s oil capacity shown on dipstick

  • An obstructed or crimped breather tube (located behind the air filter)

  • Damages to the cylinder/piston rings

Engine oil capacity is dependent on your specific engine model and can be determined by checking the Oil Recommendation FAQ.

How to Troubleshoot Engine Smoking

  • Are you tilting the engine or using it at more than a 15 degree angle? Tilting your mower or equipment can cause leaks. Right the machine before moving forward. Smoking should clear after a few minutes of running on a flat surface

  • Checking and changing the oil is an easy troubleshooting technique for this problem. Check to see if the oil is overflowing or you’re using the wrong grade/type

  • Check the crankcase for leaks

  • Is the head gasket blown?

  • Are the rings and/or cylinder worn?

You can find specific small engine repair instructions in the Briggs & Stratton Repair Manual.

WARNING: Always read the engine and equipment manual(s) before starting, operating, or servicing your engine or equipment to avoid personal injury or property damage. See an authorized dealer if you are unsure of any procedure or have additional questions. Find all Engine Safety Warnings

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