When a mower starts playing up, the question is rarely whether it can be fixed. Almost anything can be fixed. The real question is whether the fix is worth more than the machine. A useful rule keeps most of these decisions simple: if a repair costs more than about half the price of replacing the mower, you are usually better off replacing it. Around that rule sit a few details, the age and hours on the machine, the type of fault, and how many times you have already repaired it, that tell you when to spend the money and when to walk away.
The 50 Percent Rule That Settles Most Decisions
Most home mowers last around 7 to 10 years, or roughly 450 to 500 hours of running time for a typical machine, with the better-built models reaching well beyond that. The first step is to work out where yours sits in that life. A three-year-old mower with a single fault is worth fixing. A nine-year-old machine that has had two previous repairs and is now asking for a third is telling you something.
Then weigh the quote against the replacement price. A basic corded or push mower sells for as little as £60 to £120 (about $75 to $150), so almost any workshop repair on one of those will cost more than the machine is worth. A mid-range cordless or self-propelled petrol mower runs £250 to £600 (around $300 to $750), and a ride-on starts well into the thousands, so the same repair bill that would write off a cheap push mower is easily worth paying on a larger machine. The average workshop repair lands around £65 to £90 (about $80 to $110), but the spread is wide: a new battery can be £30 to £200 (roughly $35 to $250), while an engine rebuild can run from £700 to well over £2,000 (about $860 to $2,700). Put the quote next to what a like-for-like replacement costs, take half of that replacement figure, and if the repair is higher, replacement is the rational choice.
One more figure helps: the number three. As a rule of thumb, an engine that has been rebuilt or seriously repaired three times has reached the end of sensible spending. Each major repair tends to expose the next weak point, and past that count you are pouring money into a machine that will keep finding new ways to fail.
Before you commit either way, it pays to get a proper diagnosis rather than guessing. A symptom that looks like a dying engine, heavy smoke, no power, a refusal to start, often traces back to something cheap once a mechanic opens it up, such as a blocked carburettor jet, a sheared flywheel key after the blade hit a root, or a clogged deck overloading the motor. Most workshops will quote for a repair for a small inspection fee, and that quote is the number you actually need for the 50 percent rule. Putting a real figure against the real replacement cost beats writing off a fixable machine, or pouring money into a failing one, on a hunch.
Repairs That Are Almost Always Worth Doing
Plenty of mower faults are cheap, quick, and well worth fixing on almost any machine, because they are wear items rather than signs of a worn-out mower. A blunt or bent blade, a clogged or stale carburettor, an old spark plug, a dirty air filter, a perished drive belt, or a flat battery are all routine. Most of these cost a few pounds or dollars in parts and an hour of work, and they restore a tired machine to near-new performance. A mower that will not start after winter storage is far more often suffering from stale fuel or a gummed carburettor than a dead engine, and a carburettor clean or a fresh tank of fuel revives it.
On a cordless mower, the battery is the part that wears out, and replacing it is usually worth doing if the rest of the machine is sound, especially on a system where the same battery fits other tools you own. The reason these repairs make sense regardless of the mower’s age is that none of them touches the expensive core of the machine, the engine or motor and the transmission. You are replacing a consumable, not propping up a failing one. Learning to do the simplest of these jobs yourself, a blade change, a plug, an air filter, or an oil change on a petrol engine, removes the workshop labour that often tips a small repair past the point of being worthwhile.
The Faults That Usually Mean Replacement
Some problems sit at the costly heart of the machine, and on anything but an expensive mower they signal the end. A cracked or holed cutting deck is structural, hard to repair safely, and on a domestic mower rarely worth welding. A seized engine, a blown head gasket, or major transmission trouble brings repair bills that climb past £400 to £500 (around $500 to $620) for parts alone, and often well beyond, which writes off any mid-range machine on the 50 percent rule. Persistent loss of power, heavy smoking, or burning oil on an older engine usually points to internal wear that a single repair will not cure for long.
The other signal is frequency. A mower that breaks down repeatedly, needing constant small fixes through a single season, is costing you more in time and parts than its reliability is worth, even if no individual repair is large. Add up a year of those call-outs and they often exceed half the price of a replacement on their own. Rust eating through the deck, a chassis that flexes, and controls that no longer hold their setting are all signs the machine is wearing out as a whole rather than failing in one repairable spot. At that point the money is better spent on a new mower that will run for another decade than on keeping an old one limping through one more summer.
Replacement is also a chance to weigh up running costs, not just the sticker price. A petrol mower nearing the end of its life is often the moment people switch to cordless, trading ongoing spend on fuel, oil, plugs, and filters for a quieter machine with very little to service beyond the blade and battery. If you already own cordless tools from one brand, a bare mower that takes the same battery can cost noticeably less than a complete new petrol machine, which shifts the maths in favour of replacing rather than repairing the old one. Set against the repair quote, the long-term saving on servicing and fuel sometimes makes a new mower the cheaper option over a few seasons even when the old one could technically be fixed.
How to Get the Most Life Out of the Mower You Keep
Whether you repair or replace, the way to avoid this decision coming round too soon is maintenance, because most mowers that die young are neglected rather than worn out. On a petrol engine, change the oil at least once a season, keep the air filter clean, fit a fresh spark plug each year, and never leave old fuel sitting in the tank over winter, because stale petrol gums the carburettor and is the single most common reason a stored mower will not start in spring. Drain the fuel or add a stabiliser before storage, and run the engine dry.
For every machine, clean the caked grass off the underside of the deck after mowing, because trapped wet clippings hold moisture against the metal and rot the deck from beneath, which is exactly the structural failure that ends a mower’s life. Keep the blade sharp and balanced so the engine is not straining against a dull edge and a vibrating spindle. On a cordless mower, store the battery somewhere cool and dry and avoid leaving it fully flat for months, which shortens its life. A mower looked after this way commonly reaches the top of that 7 to 10 year range and beyond, and when something does go wrong it tends to be a cheap wear item rather than the engine or deck. Get the maintenance wrong and you meet the repair-or-replace question years earlier than you needed to, usually in the form of a machine that will not start on the first warm weekend of the year.
