How To Start A Briggs And Stratton Lawn Mower

Learning how to start a Briggs and Stratton lawn mower is a fundamental skill for any lawn owner. Starting a Briggs & Stratton engine reliably depends on following a consistent sequence of steps for its carbureted system. While these engines are known for their durability, a proper starting procedure ensures a long life and prevents common issues.

This guide provides clear, step-by-step instructions for both manual and electric start models. We will cover pre-start checks, the core starting sequence, and troubleshooting tips for when your mower won’t start.

The following steps outline the universal procedure for starting a walk-behind mower with a Briggs & Stratton engine. Always refer to your specific model’s manual for any unique requirements.

Step-By-Step Starting Procedure

Before you even pull the starter rope or turn the key, complete these essential checks. Skipping them is a common reason for starting failure.

Pre-Start Safety And Preparation Checks

Ensure the mower is on a flat, level surface. Clear the area of children, pets, and debris. Check the following:

Fuel: Use fresh, clean gasoline (87 octane or higher). Gas older than 30 days can degrade and clog the carburetor.
Oil Level: Check the dipstick. The oil should be at the full mark. Low oil can prevent the engine from starting due to a safety switch.
Air Filter: A clean air filter is crucial. A clogged filter restricts air flow, making the engine hard to start.
Blade Engagement: Ensure the drive and blade control levers are disengaged (i.e., the engine is not set to drive and the blade is not spinning).

The Standard Starting Sequence

Once your pre-checks are complete, follow this sequence exactly.

Prime the Engine (if equipped): Locate the primer bulb, usually a soft rubber button. Press it 3 times slowly. Do not over-prime, as this can flood the engine.
Set the Choke: Move the throttle/choke control lever to the “CHOKE” position. This is essential for a cold start.
Engage the Brake/Clutch: On most walk-behind mowers, you must hold down a lever on the handle to engage the brake. This is a safety feature that prevents the mower from moving and often must be held for the engine to start.
Pull the Starter Rope (or Turn the Key): For manual start: Grasp the handle firmly and pull the rope smoothly and quickly. Do not yank it all the way out. Allow the rope to retract gently. For electric start: Insert the key, turn it to the “ON” position, then turn to “START.” Release the key once the engine starts.
Adjust the Choke: Once the engine starts and runs roughly, move the throttle/choke lever to the “FAST” or “RUN” position within 5-10 seconds. Let the engine warm up for a minute before mowing.

Starting A Briggs And Stratton Lawn Mower With An Electric Starter

Electric start models simplify the process but require a working battery. The pre-start checks are identical.

Complete all pre-start checks (fuel, oil, air filter, clear area).
Ensure the battery is charged. If the starter turns slowly, charge the battery.
Connect the wire from the battery to the engine terminal if it’s a removable battery pack.
Insert the ignition key.
Set the throttle/choke to “CHOKE” for a cold start.
Hold down the brake/clutch lever on the handle.
Turn the key to “START” and hold it until the engine cranks and starts.
Release the key immediately after start-up and adjust the choke to “RUN.”

What To Do If Your Mower Won’t Start

If you follow the correct procedure and the engine fails to start, don’t worry. Use this troubleshooting flowchart to diagnose the problem.

Engine Does Nothing (No Sound)

Check Safety Features: Ensure the brake/clutch lever is fully engaged. Sit on the seat of a riding mower. Check that the blade engagement lever is off.
Check Battery Connections: For electric start, ensure battery terminals are clean and tight. The battery may be dead.
Check Spark Plug Wire: Make sure the spark plug wire is firmly attached to the plug.

Engine Cranks But Won’t Start

Check Fuel Flow: Is the fuel valve on? Is the gas fresh? Old gas is the #1 cause of starting problems.
Check the Primer and Choke: Did you prime 3 times? Is the choke fully on for a cold engine?
Check the Spark Plug: Remove the plug, reconnect the wire, and rest the metal base against the engine block. Pull the starter cord to check for a spark. If no spark, replace the plug.

Engine Starts Then Dies Immediately

Adjust the Choke: The engine might be flooding. Try starting with the choke off. The carburetor may need cleaning due to stale fuel.
Check Fuel Cap Vent: A clogged vent on the gas cap can create a vacuum, stopping fuel flow. Try loosening the cap slightly.

Essential Seasonal Maintenance For Easy Starting

Regular maintenance is the key to a mower that starts on the first pull every time. Neglect leads to most starting issues.

Before Each Mowing Season

Change the engine oil.
Replace the air filter.
Install a new spark plug.
Add fresh fuel with a fuel stabilizer if desired.
Sharpen or replace the mower blade.

Preparing For Winter Storage

Proper storage prevents carburetor clogs from evaporated fuel. This is the most important maintenance for easy spring starting.

Add a fuel stabilizer to the gas tank and run the engine for 5 minutes to circulate it through the carburetor.
Disconnect the spark plug wire for safety.
Drain the fuel tank or run the engine until it stops. (Consult your manual for the recommended method).
Change the oil while the engine is warm.
Clean the mower deck of grass clippings and debris.
Store in a dry, covered place.

Frequently Asked Questions

Why does my Briggs and Stratton lawn mower only start with starter fluid?

If it requires starter fluid, it indicates a fuel delivery problem. The carburetor is likely clogged with varnish from old gasoline. The engine runs on the fluid but not on the gas from the tank. Cleaning or rebuilding the carburetor is usually necessary.

How many times should I prime a Briggs and Stratton engine?

For a cold start, press the primer bulb three times slowly. Each press should feel firm. Over-priming can flood the engine, making it harder to start. If the engine is warm from recent use, one prime or none at all may be sufficient.

What is the correct choke setting for starting?

Always use the full “CHOKE” position for a cold engine start. This enriches the fuel mixture. Once the engine starts and runs, move the lever to “FAST” or “RUN” within seconds. For restarting a warm engine, use the “NO CHOKE” or “RUN” position.

Where is the model number on my Briggs and Stratton engine?

The model number is stamped on a metal shield, usually on the top or side of the engine cowling. It’s essential for ordering the correct parts. You can also find it on a sticker or in your mower’s manual. Having this number helps get specific advice.

My mower backfires and won’t start. What causes this?

A backfire during starting often points to a timing issue or stale fuel. The most common cause is trying to start a warm engine with the choke on, creating a too-rich mixture. Ensure you use the “NO CHOKE” setting for a warm restart. If the problem persists, check for a sticking valve or incorrect ignition timing, though these are less common.