21 HP Briggs and Stratton Engine Smoking?[Easy Fixing Guide]

Lawnmower engines to operate on oil keep emitting smoke from the burn. But the extent should remain confined to a minimum density.

However, a dense cloud of smoke from the engines isn’t exactly tolerable. It directly indicates a mechanical issue with the assembly.

Even the popular Briggs and Stratton mowers can’t save the trouble. Fixing the issue as soon as possible can prevent further damage.

That’s where it requires an immediate response from your side. You must catch the facts on 21 HP Briggs and Stratton engine smoking.

Different Colored Smokes from Briggs and Stratton Engine

Every mechanical lawnmower is subjected to three types of smoke – white/blue, black & white-blue combo. Each smoke originates from different mechanical issues to require a specific fix.

No need to scratch your head on how do I fix white smoke from my lawnmower. And the majority on how to solve 21 HP Briggs and Stratton engine smoking concerns white/blue emissions.

White/Blue Smokes

There are many culprits in action to cause the Briggs and Stratton engine blowing white smoke. You need to identify the reason first ahead of fixing the issue. Let’s have a look at the primary reasons behind the smoke.

  • Overloaded crankcase
  • Mismatched oil grade
  • Damaged O-rings
  • Crankcase air leaks
  • Blown head gasket
  • Invalid crankcase breather
  • Worn out cylinders
  • Sidewise tilting/turning

Lawnmower blowing white smoke and leaking oil requires further consideration, severe damage to recall extreme functional difficulty must undergo multiple checks.

You should try the down mentioned activities to address white or blue smokes –

# New purchase always induces lawn mower smoke on startup. A residual tank oil to cause the problem is pretty common.

# The most recognized solution concerns continued operation. Let the engine operate unless the smoke automatically stops.

# Keeping the mower running on a leveled ground for cutting the grass. Too many abruptic soils may cause fuel spills on the engine.

# Don’t overfill the tank with oils; it does not harm the engine. But pressure on the fuel system coincides with other issues.

Inspecting every involved mechanical part is essential to prevent white/blue smoke. Likewise, keep the fuel level reasonable within the reservoir tank. Maintain the parts at regular intervals for replacement observations.

Black Smokes

It particularly denotes a problem with the carburetor – fuel system assembly. And the action initiates a heavier fuel-air mixture than the mechanical necessity. The burning of additional fuel causes the engine to produce black smoke.

You can implement the following steps in order to resolve black engine smokes –

# Locate the air filter location in the system assembly. Loosen the connections to remove the filter from its intended place.

# Treat the filtering media to clean the aggregated surface dirt. Utilize an air compressor instead of manual attempts for a good result.

# Extremely poor conditions will require immediate replacement. Install the new filter after cleaning the slot with a damp cloth.

# Reassemble the system to check for black engine smokes. Pay attention to the carburetor for negative outcomes.

# Adjust the carburetor properly by twisting its holding screws. Look into the user manual to catch the physical specifications.

You shouldn’t operate the engine to blow smoke like its white-blue emission case. Extreme heat from excessive burning can lead to gradual engine deficiency. Always keep the air filter clean & carburetor in its intended action.

White-Blue Smokes

Sometimes, you can encounter a combination of white-blue blowing smokes. The problem actually represents early warning signs of serious issues. Several smoke-causing problems at once or complicated damage calls the problem.

You may consider the following reasons for Briggs and Stratton’s engine blowing blue smoke

  • Exceeded dipstick capacity
  • Breather tube obstruction
  • Deterioration of piston rings

How to fix 21 HP Briggs and Stratton regarding white-blue combo concerns the intended steps –

# Use the manual to understand every integrated part’s functions. Try to determine the actual reasons behind the engine smoke.

# Pay attention to every detail while disassembling the parts. Treat exterior surfaces to clean any aggregated dirt, dust, debris.

# Closely inspect individual items for proper functionality. Don’t forget to conduct tests on the connecting wires or linings.

# Try to make replacements for sensitive or important parts. Settling for at-home re-fix or repairs may initiate reappearances.

However, luck may not stand on your side every time. The existence of the smoke even after the repair indicates – erroneous implementation or further complexity.

Not to mention, the aforementioned fix is only applicable for resolving standard causes. Expert diagnosis is a must to stop the engine from blowing smoke.

Checking the oil level is a crucial part of maintaining fuel performance regarding smokes. You just need to implement the following steps –

  • Open the dipstick cap to remove the dipstick.
  • Wipe the dipstick using a clean cloth or rag.
  • Gently pull the dipstick back to the oil reservoir.
  • Take the dipstick out to reveal the actual level.

Always keep the manual in hand to tackle sudden or unexpected obstruction. Save your beginner-level skills for pro repair services to avoid misconduct.

Briggs and Stratton already prepared a detailed guide on its lawnmower engine troubleshooting. You better check the official website for further assistance.

Final Words

That’s it for our 21 HP Briggs and Stratton engine smoking solutions. Protect the engine action should appear easy without extra cost on services.

Seeing the consistent cloud of engine smoke is surely distressing for every owner. But there are simple remedies you can try at home with regular tools.

However, the aforementioned fix may not suffice on complicated issues. Don’t hesitate to consult experts or professionals to resolve difficult problems.

Leave a Comment