How Long Should a Weed Eater Warm Up?

If you have a weed eater chances are you warm it up before doing any work. But why do weed eaters need to do this? And how long does this take? Is there any risk in warming up for too long or too short? The subject might seem trivial but it makes a huge difference as you will see.

A weed eater doesn’t need a lot of time to warm up. Turn the engine on, hold the throttle for 30-60 seconds and that should be enough.

How to Warm Up a Weed Eater

Before you start, wear protective gear. Goggles, gloves, long pants, long sleeves, face shield and steel toe shoes or boots are ideal.

Follow these steps to warm up a weed whacker (or weed eater or string trimmer). This works with Troy Bilt gas string trimmers and other popular manufacturers.

1. Hold the weed whacker 2-3 inches off the ground.
2. Turn the engine on.
3. Use one hand to grab the handle and place your other hand on the trigger.
4. Hold the throttle down for 30-60 seconds.
5. Release the throttle.

At this point you can start doing yard work. It is simple enough but there are few things to keep in mind.

If you are using a gas-powered trimmer, press the primer bulb to turn the engine on. You might have to push the bulb a couple of times before the engine catches. This is how it works with Wild Badger trimmers and other brands.

If you are using a cordless or electric weed eater, press a switch or button.

Some string trimmers do not need to warm up. You can turn the machine on and use it right away. But do this only if you are sure the trimmer does not need warm up. Allowing engines to do this offers several benefits whether it is for a car, chainsaw or string trimmer.

The warm up duration varies. Most need 30-60 seconds, but older models might require 90 seconds. Refer to the manual for the recommended length. If nothing is mentioned, go with 30-60 seconds.

Why Weed Eaters Need to Warm Up

String trimmer engines receive plenty of benefits from warming up. It gives the machine time to lubricate itself. This is applicable to hedge trimmers, chainsaws, lawn mowers and other outdoor tools.

To put it simply, warming up the engine is good for weed eaters. It is best for the long term and reduces wear and tear. Following good practices like this is essential to avoid problems like string trimmers that won’t prime.

A rough analogy would be exercise. You warm up before doing any workouts to loosen your limbs and work up a sweat.

Weed eater engines are somewhat like that. Warming up ensures oil lubricates the essential parts. The few seconds you do this is enough to ready the engine.

This also gives the engine time to thin the fuel so that it spreads to all the pertinent parts. When everything is oiled up, you can run the trimmer at optimum level. Warming up also improves the performance of the carburetor.

There are other reasons why it makes sense to perform this on a weed eater.

It lets the engine fan cool off. The harder you use the trimmer, the more the fan has to work. Under difficult conditions the fan will get real hot.

Another benefit of warming and cooling is it balances engine and crankcase pressure. This is one of the keys to preventing backfiring.

How Do You Cold Start a Weed Whacker?

A cold start means starting an engine at a temperature lower than usual. This usually becomes an issue during the cold season, but it can be resolved. Once you start the engine, let it warm up as usual before trimming.

1. Wear personal protection equipment (PPE).
2. Place the weed eater on a flat surface.
3. Turn on the switch. Refer to your owner’s manual for its location.
4. Turn the choke on. This limits the air that goes into the engine. This is going to help the engine start up. You should only do this if you are cold starting the trimmer.
5. Find the press valve and press it. Check your owner’s manual for its location. The valve enables the system to draw fuel into the carburetor. You might have to press the valve 4-5 times.
6. Hold the throttle lock and pull the starter rope. Pull a few times until it catches. Note that the throttle lock is above the shaft. Under the shaft is the trigger. Do not squeeze that.
7. Keep pulling the cord until the engine runs, then stop pulling.
8. Wait 30-60 seconds for the engine to warm up.
9. After warming up, turn the choke position to off. This will normalize air and fuel flow.

This video shows you how to cold start a string trimmer.

Other Ways to Maintain a Weed Eater

Aside from warming up, there are other things you can do to prolong the life of your weed eater. Regular maintenance is a must of course, but here are some more.

Let the engine cool off before shutdown. When you are done working, let the engine cool for 30-60 seconds, same length as the warm up.

Allowing the engine to cool is good for its components. A sudden shutdown could wear out its parts due to the high temperature.

Weed eaters can get really hot, especially when doing heavy work. Combine heavy use, engine-generated heat and summer days, and that can take its toll. Cooling is a good way to preserve the engine.

Warming up is important for most weed eaters, especially older models. But so is cooling down. If you suddenly turn the engine off, nothing will prevent the gas from moving.

The fuel continues to spread throughout the engine. Since the ignition has been turned off, the fuel goes into the exhaust system and backfires. If you let the engine this will not happen.

Clean the trimmer after each use. Do not wait a month or a week after. If you used the trimmer heavily, thorough cleanup is a must to prevent dirt engine buildup and other problems. These are the kinds of issues that can prevent the trimmer from warming up properly.

Frequently Asked Questions

Why is the engine refusing to warm up?

There are many reasons why the engine refuses to start. Cold temperature, wrong fuel mixture, dirty filters, faulty spark plugs or a clogged carburetor. Check the engine components to find out the problem.

Is it true that string trimmers need up to 2 minutes to warm up?

Old string trimmers might require that much time. But newer models need only a minute or less. In fact some of them do not even require warming up, though most do. Check the manual for the ideal warming up duration.

What type of fuel is needed by string trimmers?

Most weed eaters use regular unleaded gas. The ethanol level should be 10% or lower. If you have a 2-stroke trimmer, the engine needs a mixture of gas and oil. 4-stroke engines do not mix them.

Why is the engine smoking when I start it up?

There is probably too much fuel and not enough air. This is causing the engine to release the excess gas as smoke. Just let the engine run for a couple of minutes until all the excess fuel is gone.

What happens if I do not warm up a string trimmer?

In the short term you might not notice anything different. However, this will wear the engine out over the long term. Without warm up, there is no time for the fuel to lubricate the necessary parts. This will force the engine to work harder. Eventually the parts wear out quicker too.

Which is more important, warming up or cooling down?

Both. Warming up allows the fuel to spread to all the essential parts. Cooling allows the engine to simmer down. Majority of weed eaters require both for optimum performance. The good news is it only takes a minute or less to do both.