Helping You Protect Your Home

The Definitive Guide To Lawnmower Smoke

by Bernice Stanley

There's nothing more upsetting than pulling the starting rope on your lawnmower and receiving a face full of smoke in reply. If you're like many people, this might be the moment you begin to panic. After all, your lawnmower uses an internal combustion engine similar to the one found in your car, and smoke from under your car's hood is never a good sign.

The good news is that the small engines found in lawnmowers are meaningfully different from those found in cars, and there are some less disconcerting reasons why they might smoke. Understanding why your lawnmower may be smoking will let you get to the bottom of the issue and help you decide if you need to bring your trusty push mower in for a repair.

Identifying the Source of Lawnmower Smoke

All smoke isn't the same, and looking closely at the smoke emerging from your lawnmower can provide some valuable information. You'll want to start by assessing the color. Unlike cars, most lawnmowers use air-cooled engines. As a result, there are only two potential sources of smoke in your engine: oil and gas.

Fortunately, you can usually ascertain which of these fluids is burning from the color of the smoke. Burning oil will typically produce blue or white smoke, often having a recognizably acrid smell to go along with the distinctive color. On the other hand, gas will usually result in thicker black smoke. This smoke may indicate incomplete combustion due to a rich air-to-fuel ratio.

Another useful diagnostic step is to allow the engine to run for a few minutes. While you probably want to shut down your lawnmower if it starts smoking, the problem may resolve if you leave the engine running for a minute. If the smoke goes away, there's a good chance you just had a small oil spill. However, if the smoke continues for more than a few minutes, it's time to shut the engine down and look for the problem.

Understanding the Causes of Persistent Smoke

If you're dealing with white smoke, you'll want to check your oil reservoir and determine if you have overfilled it. Too much oil will cause your lawnmower to smoke and can also result in long-term damage. While the engine will eventually burn off the excess oil, it's better to drain and fill it to an appropriate level. However, you'll want a professional to have a look if overfill isn't the problem.

For black smoke, the underlying cause is almost always a rich condition. An engine runs rich when there's too much fuel or not enough air. In cases of persistent black smoke, start by going through the usual maintenance steps for your mower. If these steps don't solve the problem, you'll want to have a professional take a look at your engine to determine if there's a more severe problem.

Call a repair company, such as Houston Equipment Repair, if you need help with a small engine.