Fall Tune-Up for Your Leaf Blower & Trimmer

Leaf blowers and string trimmers have the simplest engines we work on and the highest fall failure rate. They run a gas and oil mixture that goes bad faster than straight gasoline, and most of them sit for months with that mixture still in the carburetor. Spend an hour on yours before leaf season and it will start on the second pull all the way through Thanksgiving.

1. Start With the Fuel

If a handheld machine will not start after a layoff, the fuel is the first suspect and usually the last one you need. The pump gas sold across Kentucky is almost all an ethanol blend, and ethanol pulls moisture out of the air. Once water separates out in a small tank, what is left is corrosive and short on lubrication, and what dries in the carburetor is a varnish that blocks passages you can barely see.

• Dump what is in the tank. Drain old mix into an approved container rather than trying to run it out.
• Mix fresh, and measure. Use the ratio on the machine — 50:1 and 40:1 are the two you will see most often. Eyeballing the oil is how engines get scored or smoke badly.
• Mix only what you will burn. A month is a sensible life for mixed fuel. Ethanol-free gas, where you can buy it locally, is worth the extra cost in equipment that sits.
• Check the fuel lines and filter. The little felt filter inside the tank clogs, and the lines go hard and crack with age. Cracked lines let air in, and the engine runs lean or will not hold an idle.

Our write-up on ethanol gas and small engines goes deeper on phase separation.

2. Air Filter and Spark Plug

These two take fifteen minutes together and they separate an engine that pulls strong from one that bogs down under load. The air filter is usually a small foam or felt element behind a snap-off cover, and it loads up with dust and grass fiber fast. A plugged filter chokes the engine so it runs rich, smokes, and gives out right when you lean into a pile of wet leaves. Foam elements can be washed, dried completely and lightly re-oiled if the manufacturer calls for it; paper and felt elements get replaced.

The spark plug tells you how the engine has been running. Tan or light gray is healthy, black and sooty means rich, and wet with fuel means it is flooding or not firing at all. Plugs are cheap — on a machine that works a full season, replace it annually with the one the manufacturer specifies, gapped correctly.

3. The Spark Arrestor Screen

This is the one almost nobody checks, and it explains a lot of the "runs for a minute then dies" calls we get. Handheld two-stroke equipment has a small screen in the muffler that keeps sparks out of dry leaves and brush. Two-stroke exhaust is oily, and over time that screen plugs with carbon until the engine cannot breathe out.

It usually comes out with one small screw. Gray and open, put it back; black and crusted, clean or replace it. Never run the machine without it — in a dry Kentucky fall that is a real fire risk.

4. String Trimmer: Head, Line, and Shaft

The engine is only half of a trimmer. The other half wears in ways people ignore until the machine is unusable.

• Reload with the right line. Use the diameter your trimmer calls for; heavier line lugs the engine and wears the clutch. Line that has sat a year gets brittle, and soaking a fresh spool overnight helps.
• Wind it neatly. Crossed or loose line is the most common reason a head will not feed. Wind in the direction of the arrow, keep the coils tight and parallel, and seat the ends in the notches.
• Check the head and eyelets. The eyelets the line passes through wear into sharp grooves that cut line as fast as you feed it. Worn eyelets mean a new head.
• Grease the gearbox and clear the guard. Curved-shaft trimmers usually have a grease fitting at the head; straight-shaft machines have a drive shaft to pull, wipe and re-grease per the manual. Scrape packed grass out from under the guard, and never run the machine with the guard off — it sets line length as well as protecting you.

5. Leaf Blower: Tubes, Impeller, and Intake

A blower has fewer wear parts than a trimmer, but they matter. Start with the intake screen on the underside or back of the housing — it is the first thing to plug with leaf fragments, and a blocked intake starves the engine and kills airflow at the nozzle at once.

Then check that the tubes are seated and locked, because a loose tube bleeds off real air and people blame the engine for it. Look inside the housing at the fan blades while you are there — a chipped or cracked impeller is out of balance and will shake a machine apart. On backpack units, check the harness, frame mounts and rubber isolators for cracks.

6. The Recoil Starter

The starter rope is a wear item and it gives plenty of warning. Pull it out slowly and look at the whole length: a frayed section, a flattened spot, or a rope gone stiff and glazed means it is on its way out. Check that it retracts smartly too — a rope that creeps back in means a tired spring or debris in the housing. Replacing a rope is straightforward; replacing a broken recoil spring usually is not.

Handheld Equipment Service Schedule

Putting It Away for Winter

How you store a handheld machine in November decides how it starts in March, and the approach that never works is parking it full of untreated pump gas. Either drain the tank and run the engine until it stalls, or fill it with properly stabilized mix and run it a few minutes so the treated fuel reaches the carburetor. Then store it indoors, off a damp concrete floor. Our guide to winterizing your ATV or mower covers the larger equipment in the shed.

When to Call the Shop

Fresh fuel, a filter and a plug fix most of what keeps a blower or trimmer from starting. Past that the jobs get specialized: a carburetor that needs a rebuild kit, a machine with no spark, a recoil spring that has let go, a cracked impeller, a scored cylinder from a bad mix, or a clutch that drags at idle. Those are bench jobs, not driveway jobs.

Turf & Trail Small Engine Repair is based in Richmond, KY and serves Berea, Waco, Kirksville and the surrounding Madison County area. We work on blowers, trimmers, edgers and chainsaws from every major brand, and you get a firm quote before any work begins. If firewood is on your fall list too, our guide to chainsaw maintenance for firewood season covers the saw side of the season.

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Leaf Blower & Trimmer FAQ

How often should a leaf blower or string trimmer be serviced?
Once a year is enough for most homeowners, and fall is the right time. Fresh fuel, a clean air filter, a new spark plug and a look at the spark arrestor screen cover most of what goes wrong.

Why won't my string trimmer start after sitting all summer?
Almost always stale fuel and a gummed-up carburetor. Ethanol-blended gas draws moisture and leaves varnish behind, and a trimmer carburetor has passages small enough that a little varnish shuts it down.

What is the right two-stroke fuel mix for a blower or trimmer?
Use the ratio printed on the machine - 50:1 and 40:1 are the common ones. Measure it rather than eyeballing it, and plan to use the mix up within about a month.

Do you repair leaf blowers and string trimmers in Richmond, KY?
Yes. We service blowers, trimmers and other handheld equipment across Madison County, KY, with a firm quote before any work begins. Call (859) 661-8877.