Spring Lawnmower Service Checklist: Get Your Mower Ready for the Season

A full spring service for a petrol lawnmower takes about 45 minutes and covers nine checks: oil, air filter, spark plug, blade, deck, fuel, pull cord, wheels, and a test run. Skip any one of them and you risk the no-start, surging or vibration problems Paul fixes most weekdays through March and April.

Spring is the busiest time of year for garden machinery repair — and the most important time to get your mower serviced. After sitting idle through winter, your petrol lawnmower needs attention before that first cut of the season.

Here's the exact checklist Paul follows when servicing a mower for spring, based on over 20 years of hands-on experience repairing every major brand.

1. Check the Oil

Old oil is the number one cause of preventable engine damage. Over winter, moisture can contaminate the oil, turning it milky or sludgy. Drain it completely and refill with fresh SAE 30 or 10W-30 engine oil (check your manual for the correct grade).

2. Replace or Clean the Air Filter

A clogged air filter starves the engine of air, causing rough running, black smoke, and increased fuel consumption. Paper filters should be replaced annually. Foam filters can be washed in soapy water, dried thoroughly, and lightly oiled.

3. Check the Spark Plug

Remove the spark plug and inspect it. A healthy plug has a light tan or grey electrode. If it's black and sooty, the fuel mix is too rich. If it's white, the engine is running lean. Replace the plug if it's worn, cracked, or heavily fouled — they cost less than £5 and make a noticeable difference.

4. Inspect and Sharpen the Blade

A blunt blade tears grass rather than cutting it cleanly, leaving brown tips and making your lawn more susceptible to disease. Remove the blade and check for: - Nicks and chips (can be ground out if minor) - Cracks (replace immediately — a cracked blade is dangerous) - Balance (an unbalanced blade causes vibration that damages the engine bearings)

5. Clean the Deck

Flip the mower (disconnect the spark plug first!) and scrape off the compacted grass from underneath the deck. Built-up grass restricts airflow, reduces cutting efficiency, and promotes corrosion.

6. Check the Fuel System

If you left old petrol in the tank over winter, drain it. Stale petrol goes off after about 30 days and can gum up the carburettor. Refill with fresh unleaded. If the mower is hard to start after winter, the carburettor may need cleaning — this is the most common repair Paul sees in March and April.

7. Test the Pull Cord and Safety Features

Give the pull cord a few test pulls. It should retract smoothly with no fraying. Check that the operator presence control (the bar you hold down to keep the engine running) works correctly — this is a critical safety feature.

8. Check the Wheels and Height Adjustment

Make sure all wheels spin freely and the height adjustment moves through its full range. Lubricate any stiff pivot points with a light spray oil.

9. Give It a Test Run

Start the mower and let it run for a few minutes. Listen for: - Unusual rattling (loose blade bolt or damaged flywheel key) - Excessive vibration (unbalanced blade) - Rough idling or surging (carburettor needs adjustment) - Smoke (blue = oil burning, black = rich fuel mix, white = head gasket)

Brand-Specific Spring Tips Paul Sees Every Year

Different brands fail in different ways after winter. After two decades of Hyde workshop work, these are the patterns:

• Honda (HRX, IZY, GCV/GXV engines): Almost always a varnished carburettor when stored without stabiliser. Honda's small jet sizes make them especially sensitive to stale petrol. Check the float bowl first.
• Hayter (Harrier, Hunter, Spirit): Briggs & Stratton engines on these tend to suffer from carb gasket leaks after a cold winter. Smell test the carb — if you can smell petrol when cold, the gasket is gone.
• Mountfield (SP series, HP series): Often a sheared flywheel key from previous-season blade strikes that the owner didn't notice. If timing feels off after a winter, check the key before chasing fuel.
• Stihl (RM, MA series): Two-stroke spark plugs foul faster than four-stroke. Always check the plug colour before assuming a fuel problem.
• Briggs & Stratton (across all brands): The most common spring failure on cheaper engines is a stuck float needle. A gentle tap on the side of the float bowl with a screwdriver handle will often free it as a temporary fix — but the carb needs a proper clean.

Manufacturer guidance for petrol storage and seasonal servicing is published in every owner's manual. For Honda engines, the official Honda Power Equipment storage guidance is a useful starting point. For broader fuel safety, the UK Health and Safety Executive's guidance on petrol storage at home covers maximum quantities and approved container types.

The Three Spring Problems Paul Diagnoses Most

Every March, the same three machines come through the workshop door more than any other:

1. "It started for one second then died" — Classic varnished main jet. Fuel in the float bowl is enough for one fire, then the jet can't pass enough fuel for continuous running. Carb strip and clean. 2. "It runs but cuts out under load" — Air filter (paper filters absorb moisture and collapse over winter) or a partially blocked main jet. Always check the filter first because it's free. 3. "It vibrates so badly I can't hold it" — Almost always an unbalanced blade. A cracked or off-balance blade will destroy crankshaft bearings within a few hours of running. Stop using it immediately.

When to Call a Professional

If your mower won't start after fresh fuel and a new spark plug, or if you notice any of the warning signs above, it's time to bring it to a professional. Paul offers same-day turnaround on most spring services from his workshop in Hyde.