How to Start a Gas Leaf Blower | Correct Starting Sequence

Starting a gas leaf blower requires placing it on level ground, priming the fuel system, setting the choke to cold-start, pulling the starter rope until the engine fires, then moving the choke to run and pulling again to fully start the engine.

Standing in your driveway with a new leaf blower that won’t fire is frustrating. The starting procedure is straightforward once you understand the sequence, but small mistakes — wrong choke position, not enough primer pumps, or pulling too many times before adjusting — turn a two-minute job into a fifteen-minute headache. This guide covers the exact steps for STIHL, Husqvarna, and general 2-stroke models, what to do when the engine won’t start, and which common errors to skip entirely.

What You Need Before Starting

Gas leaf blowers run on a fuel mix, not straight gasoline. Using unmixed gas or the wrong ratio (like 40:1 instead of 50:1) causes smoking, overheating, and eventual engine damage. Fill the tank outdoors on a level surface, and keep the fuel cap tight.

You’ll also want basic safety gear on: boots, gloves, eye protection, and ear protection rated for outdoor power equipment. The blower itself needs to sit on flat, dust-free ground — never start it on a pile of leaves or in a garage.

Step-by-Step Starting Procedure for STIHL Blowers

STIHL’s handheld (BG 55, BG 65) and backpack (BR 600) models follow the same core sequence. The power switch must be in the “on” (I) position, and the master control lever should be set to the cold-start position — this is the full choke setting that closes the air intake for a cold engine.

Priming the Fuel System

Press the manual fuel pump (primer bulb) at least five times. On a cold engine, you should see fuel moving through the clear return line. If the bulb feels spongy and no fuel appears, keep pressing — air trapped in the line prevents the engine from drawing fuel on the first pull.

The Pulling Sequence

For handheld models, hold the blower firmly with your right hand against the ground and pull the starter handle with your left hand. Pull slowly until you feel resistance — that’s the compression stroke — then give a brisk, full-arm pull. Repeat this until the engine “burps” or fires once and dies. This usually happens within 2–5 pulls.

For backpack models, grip the handle with your left hand and secure the blower base with your right foot. Pull the starter handle with your right hand using the same slow-then-brisk technique.

Once the engine burps, move the master control lever to the “run” position — this opens the choke so the engine can breathe freely. Pull the starter rope again. The engine should start within 1–3 pulls. Let it idle for about a minute before squeezing the throttle; the engine needs to warm up and stabilize.

Starting a Husqvarna Blower (125B and 125BVx)

Husqvarna uses a slightly different choke and throttle sequence. The purge bulb needs to be pressed until fuel flows into the clear return tube — usually about 10 pumps, more than most people try. The blue choke lever goes to the closed position (full choke).

Set the speed control fully forward — this is full throttle, which sounds counterintuitive for starting, but the choke system on these models requires the throttle to be held open during the start sequence. Pull the starter rope until the engine puffs or fires. Do not exceed three pulls before adjusting the choke; over-pulling with the choke closed floods the cylinder.

Move the choke lever to the middle position. Pull the starter rope again. The engine should start within one or two pulls. Once it runs, squeeze the trigger and move the choke lever to the open (off) position. Let the engine idle for one full minute at warm-up before using it.

If your blower needs replacement or you’re shopping for a first unit, our tested gas leaf blower roundup compares top handheld and backpack models by real-world starting ease, air volume, and price.

Quick-Reference Start Table for Common Models

Common Mistakes That Prevent Starting

Most starting failures come from three things: wrong choke position for the engine temperature, not enough priming, or the wrong fuel mix.

Starting a hot engine with full choke is the most frequent error. After you’ve run the blower for a few minutes and then shut it off, the engine is warm. Pulling the starter with the choke closed floods the cylinder with raw fuel, making it impossible to fire. On a hot restart, try no choke or just half-choke. If you’ve already flooded it, remove the spark plug, dry it with a rag, and crank the engine a few times with the plug out to clear the cylinder.

Under-priming is the second biggest cause. The primer bulb must push fuel through the carburetor and replace the air in the fuel line. On a cold engine, five pumps is the absolute minimum — ten is better on Husqvarna models where the return tube is longer. If you don’t see fuel in the clear line, keep pumping.

Wrong fuel or stale fuel quietly kills engines. Straight gas in a 2-stroke engine will seize the piston within minutes. Fuel left in the tank over the winter absorbs moisture and leaves varnish deposits in the carburetor jets. Ethanol-free canned fuel is worth the extra cost for blowers that sit for months between uses.

Reddit users in the r/smallengines community report that a wet spark plug from over-pulling with the choke closed is the most common fixable issue — dry the plug, let the cylinder air out for five minutes, and restart with the choke open.

Troubleshooting When the Blower Still Won’t Start

If you’ve followed the correct procedure — full choke on cold engine, proper priming, correct fuel mix — and the engine still won’t fire, check these in order:

1. Spark plug. Remove it and check for wet fuel or carbon buildup. Dry it with a rag or replace it if the electrode is worn. The gap should match the manual’s spec (usually 0.025 inches).
2. Fuel line and filter. A clogged fuel filter or cracked fuel line prevents the carburetor from drawing gas. On older machines, the pickup filter in the tank can disintegrate over time.
3. Carburetor. If the engine gets spark and fuel but won’t run, the carburetor jets may be clogged from ethanol deposits. Carburetor cleaner or a rebuild kit fixes most issues, but professional cleaning runs about $60–$90.
4. Air filter. A foam filter packed with dust and oil restricts airflow, causing a rich fuel mixture that stalls the engine. Clean or replace it at the start of every season.

Husqvarna’s video demonstration shows this exact sequence.

Safety and Storage Rules

Run the blower only outdoors, at least 10 feet from any fuel or oil containers and 50 feet from people and pets. The exhaust is hot enough to melt plastic trim and start dry grass fires. When you finish for the day, let the engine cool completely before putting it away.

For off-season storage, run the carburetor dry by closing the fuel valve (if equipped) and letting the engine idle until it stalls. This prevents the ethanol in modern gas from gumming up the jets over the winter. If your blower doesn’t have a fuel valve, add fuel stabilizer and run the engine for two minutes to circulate it through the system.

Final Start Checklist

Before you pull the starter rope, run through this five-point check so you don’t waste time on avoidable issues:

• Level, outdoor surface — not in a garage or on a slope.
• Power switch in the “on” position (if equipped).
• Choke set correctly for engine temperature — full choke for cold, no choke for hot restart.
• Primer bulb pumped until fuel is visible (minimum 5 pumps).
• Fresh 50:1 fuel mix in the tank, not straight gas.