How To Start A Lawn Mower Briggs And Stratton

If you’re looking for a clear guide on how to start a lawn mower Briggs and Stratton, you’ve come to the right place. Starting a Briggs & Stratton engine reliably begins with checking a few simple things. These engines are known for their durability, but they need the right conditions to fire up smoothly each season.

This article provides a straightforward, step-by-step process. We’ll cover everything from pre-start checks to troubleshooting a stubborn engine. Following these steps will help you get your mower running quickly and safely.

The core process for starting a Briggs & Stratton lawn mower is consistent across many models. Whether you have a push mower or a riding tractor, the fundamental principles are the same. Always refer to your specific owner’s manual for model-specific details, but this guide will give you the universal steps.

Before you even attempt to pull the starter rope or turn the key, there are essential preparations. Skipping these can lead to starting failures or even damage to the engine. Let’s begin with the most important pre-start checklist.

Pre-Start Safety And Preparation Checklist

Safety should always be your first concern. A moment of preparation prevents accidents and ensures a smooth start.

Clear the Area: Remove any sticks, toys, or debris from the lawn. Ensure pets and children are a safe distance away.
Check Your Attire: Wear sturdy closed-toe shoes and long pants for protection.
Inspect the Mower: Look for any obvious damage, loose parts, or fluid leaks before beginning.
Know Your Controls: Locate the engine stop lever, throttle/choke controls, and primer bulb (if equipped).

Essential Pre-Start Checks For Fuel And Oil

An engine needs the right fluids in the right condition. These two checks are critical for starting and for the engine’s long-term health.

Checking And Preparing The Fuel System

Old fuel is the single most common reason a Briggs & Stratton engine won’t start. Gasoline begins to degrade in as little as 30 days.

Use Fresh Fuel: Always use fresh, clean unleaded gasoline with an octane rating of 87 or higher. For ethanol-blended fuel, ensure it’s less than 30 days old.
Check the Fuel Level: Ensure there is enough fuel in the tank. Running on fumes can draw sediment into the carburetor.
Consider a Fuel Stabilizer: If you store your mower for the off-season, add a fuel stabilizer to the tank before storage. Run the engine for a few minutes to circulate it through the system.
Inspect the Fuel Cap: Make sure the vent in the fuel cap is not clogged. A clogged vent can create a vacuum in the tank, preventing fuel flow.

Verifying The Engine Oil Level

Briggs & Stratton engines have a low-oil shutdown sensor. If the oil is too low, the engine will not start to protect itself from severe damage.

Place the mower on a level surface.
Clean around the oil dipstick to prevent dirt from falling in.
Remove the dipstick, wipe it clean, reinsert it fully, and remove it again to check.
The oil level should be between the “Full” and “Add” marks on the dipstick. Add the recommended oil type if it’s low, but be careful not to overfill.

Step-By-Step Starting Procedure

With safety and fluids checked, you’re ready to begin the starting sequence. Follow these steps in order for the best results.

For Engines With A Primer Bulb

Many modern Briggs & Stratton push mowers use a primer system instead of a choke. The primer bulb injects a small amount of fuel directly into the carburetor to aid cold starting.

Engage the Brake/Blade Control: For your safety, most mowers require you to hold down a lever on the handle. This lever often acts as both a brake and a blade engagement control. The engine will not start unless this is held down.
Set the Throttle: Move the throttle control to the “Fast” or “Start” position. Some models have a fixed setting.
Prime the Engine: Press the primer bulb firmly 3 times. Do not over-prime, as this can flood the engine. You should see fuel moving in the primer lines.
Pull the Starter Rope: Grasp the handle firmly. Pull the rope smoothly and briskly until you feel resistance, then give it a strong pull. Do not yank it to its full length; let the rewind mechanism retract it gently. It should start within 1-3 pulls.

For Engines With A Choke

Older or larger Briggs & Stratton engines often use a manual choke lever to enrich the fuel mixture for a cold start.

Engage the Brake/Blade Control: Same as above—hold down the safety lever on the handle.
Apply Full Choke: Move the choke lever to the “Full Choke” or “Start” position.
Prime (If Equipped): If your model has both a choke and a primer, press the primer bulb 1-2 times.
Pull the Starter Rope: Pull the starter rope with a smooth, strong motion. Once the engine attempts to fire, move the choke lever to “Half Choke” and pull again. When it starts running roughly, move the choke to “Run” or “Off.”

Starting A Riding Mower With A Key

The process for riding mowers is similar but often simpler due to electric start.

Set the Parking Brake: Always ensure the parking brake is fully engaged.
Ensure the Blades are Disengaged: The PTO (blade engagement) lever should be in the “Off” position.
Set the Choke/Throttle: Move the throttle to the “Choke” or “Fast” position. On some models, you pull the choke knob out.
Turn the Key: Insert the key and turn it to the “Start” position. Crank for no more than 5 seconds at a time. If it doesn’t start, wait 10 seconds between attempts to avoid overheating the starter motor. Once it starts, push the choke knob in or adjust the throttle to a mid-range setting.

What To Do If The Mower Won’t Start

If you’ve followed the steps above and the engine still won’t start, don’t worry. Here is a systematic troubleshooting guide to identify the problem.

Engine Does Nothing (No Pull, No Sound)

Check Safety Interlocks: Ensure the brake is set on a rider, or the handle lever is fully depressed on a push mower. Sit fully in the seat on a riding mower.
Check the Spark Plug Wire: It may have come loose. Ensure it’s firmly attached to the spark plug.
Check the Battery (Riding Mower): If you hear a clicking sound or nothing at all, the battery may be dead. Check connections and charge or replace the battery.

Engine Cranks But Won’t Fire

This is often related to fuel or spark.

Check for Flooding: If you smell strong gasoline, you may have over-primed. Wait 15 minutes, then try starting with the throttle/choke in the “Run” position.
Verify Fuel Flow: Disconnect the fuel line at the carburetor (with the fuel valve off, if equipped). Place the line in a container and turn the fuel on. Fuel should flow freely. If not, check for a clogged fuel filter, line, or tank vent.
Inspect the Spark Plug: Remove the spark plug. If it’s wet, black, or fouled, clean it with a wire brush or replace it. Check the electrode gap with a feeler gauge (typically .030 inches).
Check for Spark: Reconnect the plug to its wire, touch the metal base of the plug to the engine block, and pull the starter cord. You should see a bright blue spark. No spark indicates an ignition coil problem.

Engine Starts Then Immediately Dies

Clogged Carburetor: Old fuel leaves varnish that clogs the tiny jets in the carburetor. This often requires a carburetor cleaning or rebuild kit.
Dirty Air Filter: A severely clogged air filter restricts airflow, causing a rich fuel mixture. Remove and tap it clean or replace it.
Faulty Safety Switch: A malfunctioning interlock switch might be cutting the engine. This may require professional diagnosis.

Seasonal Starting Tips

Proper care at the end of the season makes spring starting much easier.

Preparing For Spring Start-Up

Change the engine oil before the first mow of the season.
Install a new air filter and spark plug.
Add fresh fuel to the tank.
Check tire pressure and blade sharpness.

Preparing For Winter Storage

Add fuel stabilizer to a full tank and run the engine for 5 minutes.
Disconnect the spark plug wire and drain the oil (optional, but recommended).
Remove the battery from riding mowers and store it on a trickle charger.
Store the mower in a clean, dry place.

Frequently Asked Questions

Why Is My Briggs And Stratton Lawn Mower Hard To Start?

The most common culprits are old gasoline, a dirty carburetor, a fouled spark plug, or a clogged air filter. Always begin troubleshooting with fresh fuel and a new spark plug, as these are the simplest fixes.

How Many Times Should I Prime A Briggs And Stratton Engine?

For a cold engine, press the primer bulb firmly 3 times. Do not exceed this, as over-priming floods the engine. If the engine is warm from recent use, one press or no priming is usually sufficient.

What Is The Correct Starting Procedure For A Briggs And Stratton Engine With A Choke?

Set the choke to “Full,” pull the starter rope until the engine sputters, then move the choke to “Half” and pull again. Once it runs, move the choke to “Off” or “Run.” This sequence provides the right fuel mixture as the engine warms.

Where Is The Model Number On My Briggs And Stratton Mower?

The model number is crucial for getting the right parts. Look for a sticker or metal tag on the engine cowling, often near the spark plug or above the muffler. It may also be on the mower deck frame or under the seat on riding mowers.

Can Bad Gas Cause A Briggs And Stratton Mower To Not Start?

Absolutely. Gasoline that is more than 30 days old can separate and form gums that clog the carburetor jets. If you suspect bad gas, drain the tank and carburetor float bowl, and refill with fresh fuel. You may still need to clean the carburetor.