Why is my lawn mower blowing white smoke?

Lawn mower smoking up is nothing to look forward to. Does it generate cloudy white smoke? If it does, then you are in less trouble than otherwise. In case the smoke is black or blue, you might need to consult a mechanic. But the white smoke is usually the result of oil or air (oxygen) leak to the engine. If your lawn mower smokes up when you start it, you must put some extra time to make sure your machine’s well-being. But the reason differs in different mower models. So let us five into the key reasons for your lawn mower blowing white smoke.

Precautions: you need to make sure you are wearing all the personal safety gadgets before figuring out the reason for white smoke, such as face masks, safety gloves, safety goggles, etc.

Why is my lawn mower blowing white smoke?

Exceeding the Engine’s Oil Capacity Shown on The Dipstick:

It is the first step where you basically check if any oil is coming out from the tank or if it is overflowing or not. Different engines have different capacities for fuel input. A lawn mower is a standard combustion engine machine. So, it has the approximate capacity of holding 48oz or 64 oz oil. But different models of lawn mower acquire different levels of oil. And each comes with a dipstick to check the volume. Put the dipstick in the oil tank and see if it is over capacity level or not. If it is, then this is the core reason for your lawn mower blowing white smoke.

Oil Overfill in The Crankcase:

A crankcase is the crankshaft holder inside a combustion engine. Overfilling engine oil allows the crankshaft to make contact with the oil and lead it to the crankshaft. This occurrence intrigues the oil to go to the reservoir. The swift motion of the reciprocating engine turns the oil into a froth. Thus, the smoke is built up and released in the air when you start the mower. The oil froth is the main reason why white smoke even forms.

Piston Ring Damage:

The piston rings form a seal between the prison and the cylinder wall. If these become worn or damaged, oil can leak past the rings and into the combustion chamber. Leaked oil in the combustion chamber is a key reason for white smoke. So, if you find the position damaged, it is better to replace them. Otherwise, the seal would not serve its purpose. Worn off cylinder is a significant cause for piston ring damage. The damaged rings can not be mended. It is better to replace the rings before any severe machine damage occurs.

Operating and Storing the Mower at Greater Than 15°:

The mowers are heavy machinery for gardening. You can drag them around and it is easy to use. But the basic structure of the machine is built upon a combustion engine and input of fuel (gas, oil). If the engine is placed sideways while working or storing, the structural integrity is compromised and the oil will leak into the engine, which initially will cause white smoke. Sometimes, lawn mowers need to trim uneven, rough passages. But being cautious about the right positioning will save you a lot of time, money and energy. So, avoiding tilting the engine while working and storing would be the wise thing to do.

Inactive Crankcase Breather:

Crankcase breather is the ventilation system that relieves pressure from the crankcase created by gas-fuel or extra oxygen. We already know that air leak, primely oxygen, causes the engine to blow white smoke. Here, the breather being inactive, the leaked gases can not pass through and exit the engine. Thus, when the machine is powered on, it immediately creates smoke.

Crankcase Air Leak:

Air leak is a concern. It would mean that somewhere there is a loose end, allowing air to reach the engine. White smoke can cause because the engine is exposed to air and moisture. Crankcase air leakage can link the engine to direct exposure to air. That is why the crankcase needs to be the first thing checked after checking oil measurements.

Blown Head Gasket:

If you’re using a one/two-stroke mower and notice an extreme oil leak, then, without doubt, your gasket head is damaged. The gasket head holds the fuel and keeps it separate from the other parts. A blown gasket head is the straight pass of oil to the engine. Due to extreme pressure, overwork, or oil Overfill, the gasket head might act out. That is a reason for white smoke as well. Even if have the best lawn mower available in the market, with time the gasket gets worn out.

Quick Fix:

If this is the first time you have noticed white smoke, then there are ways to prevent it from causing it again. A little maintenance workshop will do the job. Before fixing the errors, you first need to stop the white smoke. For that, you just need to run the mower free hand for a few moments till the smoke stops. It will burn off the leaked oil/air and it will be good to clean up and alter. It is an easy fix for an instant. But if your mower smokes up frequently, it will be better to get it checked by a professional mechanic. But gardening equipment like lawn mowers, leaf blowers and vacuum blowers usually work great for a long time when done proper maintenance.

Bottom line:

Sudden white smoke from your mower can catch you off guard and cause inconvenience. But it is definitely less worrying than black and blue smoke. Black smoke indicates engine irregularities and blue smoke indicates a functional error. So being able to determine which smoke is a serious threat and which ones can be dealt with with just a little maintenance is very important. And with white smoke coming out, you don’t have much to worry about. It is just some occasional oil leaks acting out. Identifying the cause of the leak and mending it would do justice, in this case. So, this is the reason for your lawn mower blowing white smoke.


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