Quick Answer: How to Start a Push Mower
To start a gas-powered push mower, place it on a flat, clear surface and check that the fuel and oil levels are adequate. Open the fuel valve if your model has one, press the primer bulb 3 to 5 times, and set the choke or throttle to the START position. Hold the handle firmly and pull the starter cord briskly until the engine fires, then move the choke to the RUN position. If the engine does not start, check for stale fuel, a flooded engine, or a dirty spark plug.
Understanding Your Push Mower Type
Before you pull a single cord or press a single button, it is important to know exactly what kind of push mower you own. The starting procedure varies dramatically depending on whether your machine is gas-powered, electric, or a manual reel mower. Following the wrong procedure can waste your time at best and cause damage or injury at worst.
Gas-Powered Walk-Behind Mowers
The most common type of push mower is the gas-powered walk-behind model. These mowers use a small internal combustion engine, typically ranging from about 125cc to 190cc, and are started by pulling a starter cord. They require fuel, oil, and regular maintenance to start reliably. Most of this guide focuses on this type because it has the most involved starting procedure and the most potential for operator error.
Electric Push Mowers (Corded and Battery)
Electric push mowers are becoming increasingly popular. Corded electric mowers must be plugged into an outdoor extension cord and are started with a simple switch or lever. Battery-powered mowers use a rechargeable lithium-ion battery and are started by inserting the safety key and pressing a button or pulling a lever. Neither type requires fuel, oil, or a primer bulb, and both are essentially instant-start.
Reel Mowers
A reel mower is a manual, engine-free device that cuts grass with a spinning cylinder of blades. It has no starting procedure at all; you simply push it forward and the wheels drive the blades. If you own a reel mower, none of the gas-engine steps in this article apply to you.
Why Knowing Your Mower Type Matters
Identifying your mower type first prevents two common mistakes: trying to pull-start an electric mower (which can damage the cord or switch) and looking for a primer bulb on a reel mower. Check the engine cowling, the owner’s manual, or the manufacturer’s label if you are unsure what type of mower you have.
Safety and Preparation Before Starting
Starting a push mower is a routine task, but it involves a spinning blade, flammable fuel, and a moving engine. A few minutes of preparation will make the process safer and far more reliable.
Safety Gear and Clothing
- Wear closed-toe shoes with good grip, preferably sturdy work boots. Never mow in sandals or barefoot.
- Wear long pants to protect your legs from debris thrown by the blade.
- Consider safety glasses or goggles, especially if your lawn contains rocks or sticks.
- Use ear protection if you are sensitive to engine noise or mow frequently.
- Keep your hands dry and free of fuel or oil before touching the starter handle.
Preparing the Mowing Area
- Walk the lawn and remove rocks, sticks, toys, hoses, and other debris that could become projectiles.
- Never start the mower inside a closed garage or shed. Gasoline engines produce carbon monoxide, which is odorless and deadly. Start the mower outdoors in a well-ventilated area.
- Make sure children and pets are at a safe distance before you start the engine.
Pre-Start Engine Checks
- Place the mower on a flat, level surface. A flat surface keeps oil distributed correctly in the engine and makes the starter cord easier to pull.
- Check the oil level using the dipstick. Low oil can prevent the engine from starting or cause serious damage. Top up with the oil type recommended in your owner’s manual if needed.
- Check the fuel level. If the tank is empty, fill it with fresh gasoline of the octane rating specified in your manual. Do not overfill.
- Inspect the spark plug wire to make sure it is securely connected to the spark plug.
- Check the air filter for obvious dirt or blockage if the mower has been sitting for a long time.
Step-by-Step: How to Start a Gas-Powered Push Mower
Once your mower is on flat ground, fueled, and oiled, follow these steps in order. The exact controls vary by brand, so always confirm the details in your owner’s manual, but this sequence applies to the vast majority of walk-behind gas mowers.
Step 1: Position the Mower on Flat Ground
Move the mower to a flat, open area of the lawn or driveway. Make sure the blade is not touching anything and that the grass or ground beneath is dry enough for good footing. If you are starting on a driveway, be aware that spilled fuel and oil can stain concrete.
Step 2: Check Fuel and Oil
Confirm that the fuel tank has enough fresh gasoline and that the oil level is within the safe range on the dipstick. If the mower has been sitting since last season, the fuel may have degraded; stale fuel is one of the most common reasons a mower will not start. When in doubt, drain old fuel and refill with fresh gasoline.
Step 3: Open the Fuel Valve
Many mowers have a fuel valve (also called a fuel shut-off) located near the fuel tank or along the fuel line. If your model has one, rotate it to the ON or OPEN position. If you skip this step, the engine will crank but will not receive fuel and will not start. If your mower has no fuel valve, simply move on to the next step.
Step 4: Press the Primer Bulb
The primer bulb is a small rubber dome, usually located on the engine cover or near the carburetor. Press it firmly 3 to 5 times. You should see a small amount of fuel appear in the bulb or in the clear fuel line. The primer pushes fuel into the carburetor to enrich the mixture for a cold start. Pressing too many times can flood the engine, so stick to the 3-to-5 range unless your manual says otherwise.
Step 5: Set the Throttle and Choke
Locate the choke lever or control. On most mowers, it is a small lever near the engine labeled with symbols or words such as CHOKE, START, RUN, or a picture of a rabbit and a turtle. For a cold engine, move the choke to the CLOSED or CHOKE position. If your mower has a throttle control instead, set it to the FAST or START position. On warm engines that have been running recently, you can often skip the choke entirely.
Step 6: Pull the Starter Cord
Stand behind the mower and place one hand on the handle to steady the machine. With your other hand, grasp the starter cord handle. Pull the cord out slowly until you feel resistance, then give it one firm, brisk pull. Do not yank the cord to its full extension or let it snap back; guide it back gently. Repeat until the engine starts. Most mowers start within one to three pulls. If the engine does not start after five or six pulls, stop and consult the troubleshooting section below.
Step 7: Adjust the Choke and Throttle Once Running
Once the engine fires and runs, move the choke lever gradually to the RUN or OPEN position. If you leave the choke closed, the engine will run rough, smoke, and may stall. If your mower has a throttle, set it to the desired cutting speed, usually FAST for most mowing conditions. Let the engine run for a few seconds to warm up before you begin mowing.
Troubleshooting: What to Do If Your Mower Won’t Start
Even with the correct procedure, a push mower can refuse to start. The good news is that most starting failures come down to a handful of common causes that you can diagnose and fix yourself.
Old or Stale Fuel
Gasoline begins to break down after about 30 days, and fuel left in the tank over the winter can turn into a varnish-like substance that clogs the carburetor. If your mower sat for months, drain the old fuel and replace it with fresh gasoline. Adding a fuel stabilizer at the end of each season helps prevent this problem.
Flooded Engine
A flooded engine happens when too much fuel enters the cylinder, usually from over-priming or from pulling the cord repeatedly with the choke closed. Signs include a strong smell of gasoline and a wet spark plug. To fix a flooded engine, wait 10 to 15 minutes for the fuel to evaporate, then try again with the choke in the RUN position and without pressing the primer. If the mower still will not start, remove the spark plug, dry it off, and pull the cord a few times to clear the cylinder before reinstalling the plug.
Dirty or Fouled Spark Plug
The spark plug creates the spark that ignites the fuel. Over time, it can become coated with carbon or oil, or the gap between the electrodes can drift out of specification. Remove the spark plug with a socket wrench and inspect it. If the electrode is black, oily, or covered in deposits, clean it with a wire brush or replace it with a new plug. Check the gap against the specification in your owner’s manual before reinstalling. A worn or fouled plug is one of the most common reasons a mower cranks but will not start.
Air Filter Problems
A clogged air filter starves the engine of air, making the fuel mixture too rich to ignite. Remove the air filter cover and inspect the filter. If it is dirty, clean a foam filter with soapy water or replace a paper filter. Never run the mower without an air filter, as dirt will enter the engine and cause damage.
Quick Troubleshooting Reference
| Symptom | Likely Cause | Simple Fix |
|---|---|---|
| Engine cranks but will not start | Stale fuel, no fuel reaching carburetor, or fuel valve closed | Open the fuel valve, check fuel freshness, refill with fresh gas |
| Strong gas smell, wet spark plug | Flooded engine from over-priming or excessive pulling | Wait 10-15 minutes, start without choke and without priming |
| Engine starts then dies | Choke left closed, dirty air filter, or clogged carburetor | Move choke to RUN, clean or replace air filter |
| No spark at all | Fouled spark plug or disconnected plug wire | Reconnect wire, clean or replace spark plug |
| Engine will not turn over | Low oil, seized engine, or broken starter cord | Check oil level, inspect starter assembly |
If you have worked through all of these checks and the mower still will not start, the problem may be a clogged carburetor or a failing ignition coil. These repairs are best handled by a small-engine shop unless you are comfortable with carburetor service.
Starting an Electric or Battery-Powered Push Mower
If your push mower is electric, the starting procedure is much simpler, but it still has its own safety requirements.
Corded Electric Mowers
- Plug the mower’s power cord into a grounded outdoor extension cord rated for the mower’s amperage.
- Route the extension cord away from the cutting path so you do not run over it.
- Press and hold the safety handle (usually a two-handed operation) and flip the start switch or pull the start lever.
- Release the switch to stop the mower. The blade stops quickly on most modern models.
Battery-Powered Mowers
- Insert the charged battery into the mower until it clicks into place.
- Insert the safety key if your model uses one.
- Press the start button or squeeze the start lever while holding the handle.
- To stop, release the lever or press the stop button. Remove the safety key when storing the mower to prevent accidental starts.
Electric mowers eliminate fuel, oil, and pull-cord problems entirely. The main pre-start checks are ensuring the battery is charged, the cord is undamaged, and the blade is clear of debris.
Frequently Asked Questions
How many times should I press the primer bulb before starting?
Most manufacturers recommend pressing the primer bulb 3 to 5 times on a cold engine. You should see fuel appear in the bulb or the clear fuel line. If the engine is warm from recent use, you can skip priming entirely. Over-priming can flood the engine, so if you smell gasoline strongly, stop priming and wait a few minutes before trying to start.
Why does my push mower start but then immediately die?
The most common cause is leaving the choke closed after the engine fires. Move the choke lever to the RUN position as soon as the engine starts. Other causes include a dirty air filter, stale fuel, or a clogged fuel line. Work through the troubleshooting table above, starting with the simplest fix.
Do I need to use the choke every time I start my mower?
No. The choke is only needed for a cold start. If the engine is warm, such as when you stop to empty the grass bag and restart, you can usually start without the choke and without pressing the primer. Using the choke on a warm engine can flood it and make starting harder.
Can I start my push mower on grass or should I move it to pavement?
You can start a push mower on grass as long as the ground is flat and level and the area is clear of debris. Starting on pavement is convenient for checking oil and fuel, but be aware that any spilled gasoline or oil can stain concrete. The key requirement is a flat, stable surface so the mower does not tip and the oil stays where it belongs.
