Riding mowers are surprisingly durable but like all kit, they break down. The good news is, the root cause of the no start tends to be easily fixed. I’m a mower mechanic and I’ve been fixing and maintaining these mowers for years. You are in the right place and very shortly I predict the sound of a sweet running mower.
Riding mowers can not be push-started or tow-started. Instead, they may be jumpstarted or alternatively, Hotwire started. The most common causes for a nonstarting riding mower include a flat battery, dirty fuel system, and faulty starter solenoid.
In this post, you’ll learn why you can’t push start your riding mower. You’ll learn how to jump-start your mower and you’ll learn some common causes of a no-start riding mower together with links to posts and videos that will help you fix them like a pro!
Why You Can’t Push Start a Riding Mower
A riding mower can’t be push-started, although the engine is coupled to the rear axle via belt and pulleys it won’t transfer lateral motion of the belt into rotational motion of the engine. There are two common riding mower transmission types, the oil-driven Hydrostatic tranny, and the manual transmission.
Attempting to push-start either type will not result in engine rotation. Both types are driven by a belt that is tensioned by a floating drive belt pulley tensioner. While the tensioner pulley does its job and maintains belt tension across the whole system, the belt will only transfer drive when drive originates at the engine crankshaft pulley.
Attempting to push start a riding mower causes drive to originate at the transaxle pulley, this results in belt slack, and slip at the engine crank pulley.
Alternative Ways To Start a Riding Mower
A flat battery is a very common cause of a non-start riding mower. And the fastest solution to that particular problem is a jump-start (covered below). That said a flat battery isn’t the only cause of no-starts and worse, some faults actually mimic a flat battery and I covered them a little later.
Another common no start issue is believe it or not – incorrect starting procedure. All mowers employ safety lockout switches. They are fitted to seats, parking brake controls, hood, blade levers, etc. If the correct procedure isn’t followed, the mower engine may not crank over or start depending on how the system is designed. I’ve covered starting a mower in a little more detail here.
When attempting to start a flat riding mower we have a few options and here they are.
Jump-staring (also known as boost-starting) is the easiest and fastest solution to a flat riding mower battery. Jump-starting is a process where we scavenge the power needed to start our mower from another vehicle’s battery. Any twelve-volt battery will do the job. It’s possible to jump-start a mower from a car, truck, another mower, an ATV, etc., once it has a 12v battery it’s suitable to jump start.
How do you know if a vehicle has a twelve-volt (12 v) battery? It will state it clearly on the battery casing, usually, a sticker stating voltage, amp-hour, CCA, etc. I’ve covered the whole jump-starting process here in this post.
Many no-start mowers suffer from loose or dirty battery wires, it’s worth taking a moment to check both negative and positive battery terminals are clean and tight.
As an alternative to using a car to jump from try a boost pack. You’ll find the mighty NOCO boost pro pack here on the Small engine tools page. The NOCO is capable of jumpstarting your mower, truck, car, ATV, RV. It’s an incredible little tool that’s small enough to fit in your glove box yet packs a real punch.
As an alternative to jumpstarting your mower try charging the battery instead. Battery charging may take as little as thirty minutes or a couple of hours, depending on how low the battery is and the Amp rating of the charger.
You’ll find a top-class smart charger on the Small engine tools page.
Hot wiring your mower is possible, but won’t work if the battery itself is at fault. I use Hot wiring when fault-finding ignition system components. Hot wiring may be performed at the starter motor or at the starter motor solenoid.
In order for hotwiring to be successful, the ignition must be set to position two – ignition “On”.
The mower must be placed in park and the blade disengaged as Hot wiring bypasses all the safety systems. I’ve covered Hot wiring previously while troubleshooting a starter motor system and you can check it out here “Riding mower won’t start just clicks”.
Some older mowers may have a pull starter in addition to a starter motor. Riding mowers don’t actually need a battery to stay running as they employ an alternator that produces all the power they need to operate lights, solenoids, etc. Point is, while not ideal, it is possible to buy and fit a pull start assembly.
The pull start makes the battery, starter, and starter solenoid redundant and is a real alternative to buying a new battery, starter, etc.
Common Causes Of No Start Riding Mowers
The list below doesn’t include all the possible issues that prevent a riding mower from starting but it does include all the relevant causes that result or mimic a battery issue and all these issues listed are common riding mower problems.
I understand you may or may not know why your riding mower won’t start. And so I’ve categorized a selection of symptoms into various buckets to aid in identifying which action will best suit your likely riding mower issue.
Remember, some faults mimic a flat battery when in fact the battery and ignition system is not at fault. All relevant symptoms and faults are covered below.
Battery Issue Symptoms – Bucket 1
- Mower clicks repeatedly when the key turned
- Mower makes no noise when key turned
- Engine cranks over slowly when key turned
Likely fault – Flat, faulty battery, or loose battery terminals
Action – Check battery terminals are tight and clean and attempt the jump start procedure
Solenoid Issue Symptoms – Bucket 2
- Engine clicks once when the key is turned
Likely fault – Starter solenoid faulty
Action – Replace starter solenoid
Fueling Issue Symptoms – Bucket 3
- Engine cranks over but then stops
- Gas leaking from muffler
- Engine oil level is overfull
- Smell of raw gas
Likely fault – Carburetor float needle is worn and leaking – Hydrolocking
Action – Replace carburetor float needle valve
Ignition Issue Symptoms – Bucket 4
- Engine makes no attempt to crank when key turned
Likely fault – Control module fault or safety lock-out switch issue
Action – Check starting procedure is correct and then check the control panel
Engine Issue Symptoms – Bucket 5
- Engine cranks over then stops
Likely fault – Valve lash out of spec
Action – Check and adjust valve lash
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John Cunningham is an Automotive Technician and writer at Lawnmowerfixed.com.
He’s been a mechanic for over twenty-five years and shares his know-how and hands-on experience in our DIY repair guides.
Johns’s fluff-free How-to guides help homeowners fix lawnmowers, tractor mowers, chainsaws, leaf blowers, power washers, generators, snow blowers, and more.