Michael Turner
Fuel mix: use fresh unleaded gasoline (87–93 AKI) mixed at the manufacturer’s two-stroke ratio – many modern units use 50:1 (20 ml oil per 1.0 L fuel or ~77 ml oil per 3.785 L / 1 US gal). Avoid fuel older than 30 days; if storage is required, add a fuel stabilizer per label (typical dose ~1 oz per 2.5 gal) or drain the tank.
Primer and choke routine: with the tool on a flat surface and straps unbuckled, press the primer bulb 3–5 times (no more). Set choke to FULL for cold starts; if warm, set to OFF or HALF as specified in the manual. Pull the starter cord until you feel resistance, then give 3–6 brisk pulls – if the unit coughs or runs briefly, immediately move choke toward RUN/OPEN and pull once more. Excessive pulls (>8) increase backfire risk and fatigue starter components.
Pre-operation checklist (do these every time): confirm fuel cap is tight and venting; inspect air filter for heavy debris and replace or clean if oily/dirty; check spark plug for light tan insulator and a gap commonly around 0.6–0.7 mm (0.024–0.028 in) depending on model; verify fuel lines are supple with no cracks; ensure throttle trigger, kill switch and straps move freely. Replace a fouled plug before attempting additional pulls.
Warm-up and idle: after the engine fires and choke is off, let the unit idle for 30–60 seconds to stabilize temperature and oil circulation. Confirm steady idle and smooth throttle response before applying full throttle; if the engine hesitates or surges, shut off and re-check air filter, spark plug condition and correct fuel mix.
Safety and care: wear hearing protection, eye protection and gloves; secure the shoulder harness snugly and test strap buckles under load. Keep the exhaust/muffler area clear of obstructions and combustible material. For long-term storage, run the engine dry of fuel or use stabilizer and fogging oil per service instructions to prevent carburetor gum and corrosion.
Get a two-stroke leaf unit with harness to ignite reliably
For a cold engine: choke CLOSED, primer bulb pressed 4–6 times until fuel is visible, fuel valve ON, then deliver firm, controlled pulls on the recoil rope – expect ignition within 3–5 pulls on a warm unit and 6–12 pulls below 10°C.
Pre-operation checklist
- Fuel: use fresh gasoline mixed with 2‑cycle oil at 50:1 for modern small-engine units (40:1 only for models that specify it). Mix in a clean container; discard fuel older than 30 days unless treated with stabilizer.
- Primer: press until bulb fills; if it won’t hold fuel, inspect primer diaphragm and fuel line for leaks or cracks.
- Ignition switch: set to RUN (not STOP) and verify kill switch wiring is intact; a faulty switch gives intermittent sparks.
- Air filter: clean or replace if clogged; restricted airflow causes hard ignition and heavy smoke.
- Spark plug: gap 0.70–0.80 mm (0.028–0.031 in); replace if fouled, wet with fuel, or cracked porcelain.
- Muffler/exhaust port: remove carbon buildup periodically; severe restriction prevents ignition or causes stalling.
- Harness and straps: adjust so machine rides high on hips; excessive sag increases starter rope angle and makes pulls harder.
Controlled pull technique and adjustments
- Position unit on level ground (or between knees if handheld), choke CLOSED for cold, throttle set to half or tick-over depending on model controls.
- Grip rope handle with thumb wrapped under for secure pull; pull smoothly until you feel compression, then use a brisk arm motion – avoid jerking the rope from the shoulder only.
- If engine floods (strong fuel smell, wet plug): move ignition to OFF, remove plug, pull rope until fuel clears, dry or replace plug, then reinsert and repeat priming with choke OPEN one notch.
- After first ignition: open choke to HALF until engine runs smoothly; once at consistent idle, move choke to RUN or fully open to avoid bogging and fouling.
- Cold-weather tip: warm hands and keep fuel warm (store container indoors) – thicker oil in subzero temps increases required pull count; use synthetic 2‑cycle oil rated for low temperatures if available.
- Troubleshooting: no spark – remove plug, connect plug to mating terminal and crank (use insulated pliers); visible blue spark means ignition circuit OK; if no spark, inspect coil, kill switch, and wiring.
- Fuel delivery check: with plug out and ignition OFF, press primer – fuel should enter cylinder when pulling rope; absence indicates clogged line, stuck tank valve, or dirty carburetor inlet.
- Limit pulls to 15 per session; excessive attempts flood the engine and wear the recoil. If not igniting after 10–15 pulls, inspect rather than continuing attempts.
- Regular maintenance: replace fuel lines every 2–3 years, clean carburetor jets annually if used heavily, and store drained of fuel for winter storage to avoid varnish formation.
Fuel and oil: prepare correct two-stroke mix and fill the tank
Mix 50:1 gasoline-to-oil – 2.6 fl oz (≈75.7 ml) two-stroke oil per U.S. gallon or 20 ml oil per liter; use fresh unleaded gasoline 87–93 AKI with maximum 10% ethanol (E10), avoid E15 and fuels older than 30 days.
Mixing procedure
Use an approved plastic fuel can and a calibrated measuring cup. Pour the measured oil into the empty can first, add roughly half the gasoline, cap and invert 10–15 times to create an even emulsion, then add the remaining fuel and repeat inversion. Mark the container with the 50:1 ratio and the mix date. Dispose of any mixture that is cloudy, has visible separation, or is older than 30 days.
Tank filling and checks
Place the unit on a level, cool surface outdoors. Open the fuel cap slowly to relieve pressure, use a funnel or spill-proof spout, and fill leaving about 6 mm (1/4″) headspace for expansion; do not overfill. Inspect the tank strainer and inline fuel filter – replace if discolored, brittle, or clogged. Wipe spilled fuel from surfaces, tighten the cap securely, and store remaining premix in an approved container away from heat and open flame.
Inspect straps, air filter, spark arrestor and throttle linkage
Inspect straps and harness before each use: reject and replace any webbing with frays, cuts deeper than 50% of thickness, unraveling stitches or hardware corrosion. Measure elongation; discard straps showing >10% permanent stretch. Check buckles, D-rings and quick-release clips for cracked plastic, bent metal or seized swivels; padding compressed more than half its original thickness should be swapped out. Clean webbing with warm water and mild detergent, air dry; do not machine-dry or apply solvents to fabric.
Remove the airbox cover and inspect the element visually and by feel. Foam element: wash in warm soapy water, squeeze until clear, air dry, then soak lightly in two-stroke oil and wring out excess; replace if torn or brittle. Paper element: tap out dry dust, replace if contaminated with oil or damaged. Use low-pressure compressed air (<30 psi) from clean side out only if element is serviceable. Service interval: every 5 hours in dusty conditions, every 25 hours in normal use; replace annually or sooner if compromised.
Allow the unit to cool for at least 15 minutes and disconnect the ignition lead before accessing the muffler. Remove the muffler cover and inspect the spark arrestor screen for perforations, thinning or carbon build-up exceeding ~1 mm. Clean by soaking in a commercial carburetor cleaner or hot degreasing solution and brushing with a brass wire brush; replace the screen if any holes, severe thinning, or persistent clogging remain. Replace any damaged muffler gasket and torque fasteners to the specification printed on the service manual. For sticky, small-part deposits try this cleaning guide: how to clean cat eye gunk.
Check throttle linkage and safety circuitry with the ignition lead disconnected. Required free play at the remote lever: 2–4 mm before the linkage begins to move the carburetor arm. Full travel must be smooth, with immediate positive return by the spring; any stickiness, binding or visible frayed cable strands mandates replacement. Lubricate pivot points with a few drops of light machine oil; avoid contaminating the air filter. Verify kill-switch wiring and connector condition and confirm switch opens the ignition circuit when actuated.
Wear cut-resistant gloves and eye protection while inspecting and cleaning. Reassemble only after all fasteners, gaskets and screens are fitted correctly and the ignition lead is reconnected per the service checklist.
Set controls for cold conditions: ignition on, choke position, and primer bulb usage
Ignition: Move the on/off switch to the ON or RUN position (marked I or RUN). Verify the kill/stop switch is not engaged and the spark arrestor cap is secure. Do not press the primer bulb while the ignition is OFF unless specified by the model manual.
Choke selection by ambient temperature: For air temperatures below 10°C (50°F) set to FULL CHOKE (closed choke). For 10–18°C (50–65°F) use HALF CHOKE. For temperatures above 18°C (65°F) place choke to RUN/open. If engine has a cold-assist lever labeled COLD/WARM, use COLD with temperatures under 10°C and WARM above 18°C.
Primer bulb routine: Press the primer 3–5 times; stop when the bulb fills and feels firm. Do not exceed 6 presses – repeated priming can flood the carburetor. If the bulb stays collapsed after 6 presses, inspect fuel lines and primer for air leaks before continuing.
If flooding occurs or unit fails to respond: Move choke to RUN/open, leave ignition ON, and pull the starter gently 3–4 times to expel excess fuel; do not press the primer during this clearing. If the spark plug is soaked, allow it to dry or replace it before further attempts. After clearing, use 1–2 light primer presses and the appropriate choke setting for the current temperature.
Execute the pull-routine: finding compression, proper grip, and controlled pulls
Detect compression
Slowly pull the cord until you meet a distinct, firm resistance–this is the compression stroke. The resistance typically appears in the final 6–10 inches of cord travel; stop when the rope tightens and does not rewind freely. A correct compression feel is steady, not a sudden hard stop; if the cord snaps back, you pulled past the point. If the rope shows no resistance after three slow attempts, inspect ignition and flywheel area before further attempts.
Grip, body position, and pull mechanics
Stand with feet shoulder-width apart, place the unit on level ground with the intake facing away. Use your non-dominant hand to secure the housing (palm flat over the fan cover or handle) to prevent lateral movement; do not grip the recoil handle while bracing. With the dominant hand, close around the starter T with thumb alongside the grip (not wrapped behind the rope), wrist straight. Pull in a smooth, continuous motion using shoulder and torso rotation rather than just the elbow. Aim the pull roughly 30–45° upward from horizontal so the rope unspools cleanly and the recoil springs engage correctly.
Apply a full-arm extension on each pull; do not yank. After each pull, allow the cord to return slowly under control to avoid rope damage and reduce recoil stress on the spring. Keep the free hand clear of any moving parts and the trigger/thumb away from the throttle linkage until the engine runs steadily.
Use a sequence of 3–6 firm pulls for a typical cold attempt. If the unit fires briefly but does not continue running, move the choke to the next position (per the manufacturer) and give one or two additional controlled pulls. If there is no ignition after 6–8 proper pulls, stop and troubleshoot electrical, fuel, or spark plug issues.
Wear gloves with a grippy palm and eye protection. Never wrap the cord around your hand; do not allow the rope to slap the housing. For transport options or carrying alternatives when moving between jobs, consider a supportive pack or messenger solution such as best tennis backpack for men or best messenger bag for guys.
Warm the engine, adjust the choke, and troubleshoot flooding or stale fuel
Set the choke to HALF after the engine first fires, hold throttle at roughly 30–40% for 30–60 seconds, then move the choke to OPEN and run another 15–30 seconds before full-throttle use.
If the unit was already warm, place the choke at OPEN and pull once or twice; only use HALF choke for very brief warm-up (5–15 seconds) to avoid fouling.
Limit primer-bulb strokes to one or two on a cold unit; more than three fills the carb and causes flooding. Mark the bulb with a small dot to avoid repeated presses during routine handling.
Flooded-engine procedure: switch ignition OFF, remove the spark plug, wipe or replace the plug if saturated, hold the throttle at full-open and pull the recoil 5–10 times with the plug removed to expel excess fuel, reinstall a dry plug, set choke to OPEN and pull to fire.
Stale-fuel recovery: drain the fuel tank and run the carburetor until fuel lines are empty; dispose of old mix in approved container. Replace inline fuel filter and any brittle fuel hose. Refill with fresh premix at the specified ratio (commonly 50:1–confirm with the unit’s data plate) and use gasoline less than 30 days old unless a stabilizer was added.
Spark plug checks: gap 0.020–0.024 in (0.5–0.6 mm); light tan electrode indicates correct mixture, black and wet indicates rich (excess fuel), white glaze indicates lean or overheating–replace if fouled or damaged.
When diagnosing persistent no-fire or rough-running issues, verify: charged ignition (kill switch functioning), clean air filter, unobstructed spark arrestor, free-moving throttle linkage, and a firm fuel flow from tank to carb. Replace suspect components in the order: fuel, plug, filter, then carb service.
| Symptom | Likely cause | Corrective action |
|---|---|---|
| Engine cranks but won’t ignite | No spark or stale/foul fuel | Check kill switch continuity; remove plug to check spark and gap; replace fuel with fresh premix and prime once. |
| Strong fuel smell; plug wet; no combustion | Flooded cylinder (excess primer or choke) | Turn off ignition, remove plug, wipe/dry or replace, pull recoil 5–10 times with plug out, reinstall plug dry, set choke OPEN, attempt ignition. |
| Fires then dies | Air leak, blocked fuel flow, or choke still closed | Inspect fuel line and filter, ensure choke is HALF→OPEN as engine warms, check carb mounting gasket and intake boots for leaks. |
| Rough idle or surging | Dirty air filter, clogged spark arrestor, or poor fuel quality | Clean/replace air filter and spark arrestor, drain old fuel and refill with fresh premix, check idle screw setting per manual. |
| Runs only with choke on | Lean mixture or carb float/jet blockage | Inspect carb for varnish or debris; if cleaning doesn’t help, rebuild or replace carburetor assembly. |
FAQ:
Why won’t my Echo backpack blower start after I pull the cord?
Check a few common causes: make sure the ON/OFF switch is set to ON and the fuel valve (if present) is open. Confirm the fuel has the correct oil:fuel mix per the blower’s manual (many Echo models use 50:1). If the engine doesn’t even try to fire, inspect the spark plug for fouling or a bad gap and replace it if worn. A clogged air filter or blocked fuel line can prevent starting, as can stale fuel. If the engine sputters but won’t run, try the choke and primer steps (see your manual), and ensure the primer bulb has been pressed the recommended number of times. If you still have trouble, a qualified small-engine technician can run a compression and carburetor check.
How should I set the choke and primer for a cold start on an Echo backpack blower?
Follow these steps: move the master switch to ON, press the primer bulb the number of times shown in the manual (typically 3–5). Set the choke to the closed or “CHOKE” position for a cold engine. Place the blower on firm ground, hold the tube steady, and pull the starter rope until the engine coughs or briefly fires. When it does, move the choke to the half or RUN position and pull again until it starts. Once running, release the choke fully so the engine runs smoothly. If it floods (lots of fuel smell and won’t fire), open the choke, hold the throttle at the starting position, and pull until it clears; repeat the primer routine more sparingly next time.
