Tractor Mower

lawn tractor won't start no click

Before we assume there's a problem, lets take take a minute to check that we're following the correct starting procedure. All mowers will have safety sensors fitted, and if the sensors are open, it won't start.

So why won't your lawn tractor start, not even a click? The most common reason for a no start, not even a click sound, is a totally flat battery, but other likely causes include:

 

  • Transmission in Drive
  • Brake Pedal not Pressed
  • Blade Switch / Lever On
  • Not Sitting in Seat
  • Bad Battery Connection
  • Sensor Faults
  • Flat / Faulty Battery
  • Main Fuse Blown
  • Faulty Ignition Switch
  • Faulty Control Module

A tractor mower won't start if the blade lever/button is on, manual mowers need to be in Neutral gear, some mowers won't allow starting if the oil level is low or the hood is open.

 

If your in any doubt about the correct starting procedure for a lawn tractor, check out - "How to Start Husqvarna Ride-on Mower".

 

If you do hear a click sound when you turn the key, check out - "Mower Wont Start Just Clicks".

Check Battery & Connections

To test a battery you need a volt meter, but if you don't have one try this basic check. If your mower has hood lights, or dash lights go ahead and turn them on. If they light up and are bright, your battery is most likely not the problem. 

Dash Lights are Dim

Check the battery cables – they should be clean and tight. When connections are loose or corroded, it prevents available power flowing to the starter.

Charge your battery – If your battery is completely flat, it will take a couple of hours and will require a battery charging hack. 

Jump start mower – This is the fastest solution, but it may not be the long term fix.

Mower dash lights

Volts

Turn on the lights to check for power supply.

If they work - the battery is OK.

If lights are dim - Check battery cables - if OK charge battery.

Mower battery lead Mower battery lead

If you have no lights - Need a volt meter to check battery voltage 12.65v is 100%, 12.30v is 70%, 12.05v is 50% charged.

Don't have a charger - no problem, Jump Start Mower.

Dash Lights Don't Work

Check battery state of charge - Very low volts, it's likely the battery is faulty and will not recharge.

 

Check the main fuse - all mowers will have one, the hard part is finding it. 

 

Volt Meter

If the lights don't work at all, you'll need to buy or borrow a Digital volt ohm meter (Dvom) to check battery state of charge - if you have very low volts, it's likely the battery is faulty. The average life of a battery is 4 years, more if well cared for.

 

Jumper Cables

If you don't have a charger, you can still get it running but you'll need a set of jumper wires and a car or any 12volt battery will do the job. Follow this link for a guide to Jump Starting.

 

mower jump starting cables

Jumpers

Use good quality jumpers, if your unsure how use them check out Jump Starting Guide.

Testing mower battery

Volt Meter

If you have no lights - Use a Dvom to check battery voltage 12.65v is 100%, 12.30v is 70%, 12.05v is 50% charged.

Main Fuse

If the battery is fully charged and still no go - check mower main fuse. Some mowers will have the blade type fuse, others will have the old style bottle type.

 

When it blows all power is lost, changing it is simple. It is important to replace the fuse with the correct amp rating. If the fuse keeps blowing - fuse rating is too low or there's a short to ground wiring fault. 

 

Places they like to hide them include, under seat, under hood, behind fuel tank, incorporated into the Control module. 

 

Location

Places they like to hide them include, under seat, under hood, behind fuel tank, incorporated into the Control module. Modules are usually under the dash panel. 

 

Mower main fuse

Fuse

When the main fuse blows, all power is lost.

Sometimes they can be hard to find.

Replacing is simple, just pull out the old one and replace.

Mower fuse Mower battery lead

It's important to replace it with the correct rating, otherwise you can damage the wiring circuit and components.

Check Safety Sensors

Riding mowers are designed with safety features built in to protect us from operator error or accident. Safety features on mowers are controlled by sensors/switches and most modern mowers will wire those sensors into a control module.

 

The sensors are a very simple on/off switch type and rarely give trouble, it's more common for the striking plate that pushes on the sensor to be misaligned, when this happens, the sensor is open and the engine won't start or stops depending on where the sensors fitted.

 

Starting Procedure

As you know, there's a starting procedure which must be followed before your mower will start. You can check out the starting procedure here - How to Start a Husqvarna Ride-on Mower.

 

There are several sensors which must be engaged, the location and number of sensors are dependent on the make of mower and differs between manual and hydro-static (type of transmission).

 

The main sensors are: brake pedal; seat; gear lever; blade engage control switch or lever and some models such as John Deere will have one fitted to the hood (Hood open - no start).

 

Overriding

Sensors can be overridden for test purposes, remove and join the wires, some sensors are wired in reverse - meaning, just disconnecting them will override the sensor. You can check sensors for continuity using a volt meter.

 

Mower main fuse Mower fuse

Safety

For our safety sensors are fitted to the seat, blade engage lever or button, transmission selector, brake pedal and on some models the hood.

Any of these sensors will prevent your mower from starting.

Mower battery lead Mower battery lead

On older manual transmission mowers the gear selector wears and although the selector points to the Neutral position its often still in gear - confirm its in Neutral by pushing it forward or back, it should be easy to push.

Mower blade lever Mower blade control lever

Sensors

This older style Craftsman / Jonsered / Husqvarna blade lever causes lots of no start problems.

The lever spring gets weak and leaves the sensor in the open position which prevents starting.

The quick fix - hold down the lever to start the mower. The complete assembly is available and not too difficult to fit.

Check that all sensors are working, look to see the striker plates are closing the sensors fully.

Mower battery lead

Check wiring to sensors for chafing and that the connectors are secure and free from corrosion.

Check Control Module

Most modern mowers will have a Control module, they are a printed circuit with relays and resistors - they do give trouble. Because the specs vary, I can't be more detailed.

 

The function of the control module is to receive a start/stop command from the ignition switch, and only out put a start command to the starter (via the solenoid) if all the correct sensors have been engaged.

 

Wiggle Test

Have a helper sit on the mower and attempt a start while you wiggle the wires at the back of the control module. Often this will show you where exactly the fault is.

 

You can visually inspect these modules for loose connections or water damage to the printed circuit. All modules will have a fuse either internal or external - Check it.

 

Main Fuse

All modules will have a fuse either internal or external. As you know the main fuse in a mower can blow, and if it does, it will kill the power to the ignition system.

 

mower starter module mower starter fuse

Module

Modules could be fitted anywhere, they are usually fitted inside a hard plastic box about the size of a mobile phone.

Not all mowers will have one fitted, but most will.

Wires come loose, have a helper attempt to start the engine while you wiggle the wiring connectors.

Check also for damage, water or scorch marks on the panel itself.

Check Ignition Switch

Ignition switches are an important part of the ignition system, bad connections here can cause lots of problems. Ignition switches - send commands to the control module if fitted.

 

If your mower doesn't have a control module, then the safety sensors are wired inline to the ignition switch - meaning any sensor that is in the open position will leave the ignition switch with an open circuit (No start). These systems are basic and tend to be the most reliable.

 

Common Problems

Issues with ignition switches: loose wiring at switch; corroded terminals; broken terminals; spinning ignition switch's.

 

Wiring specs for ignition systems vary, so I can't be more detailed. Check the ignition wiring for damage, corrosion or loose wires. Have a helper sit on the mower and attempt a start while you wiggle the ignition wires and connectors.

 

If you have a Dvom:

Check ignition inputs - ground and 12 volt supply.

Check ignition outputs - 12v to the starter solenoid (or to the Control module if fitted) when ignition is in the start position.

 

Ride-on mower key

Switch

Spinning ignition switch's causes damage to the wiring and pins.

Corrosion is another common failure. This usually causes unreliable starting and shut downs.

mower ignition

Wiggle

Try wiggling the wires at the back of the ignition switch while attempting to start the engine, you may need a helper.

Often wires simply come loose, but do check them for corrosion.

Related Questions

Lawn mower ignition switch problems? Common Ignition switch problems, include:

  • Spinning ignition switch
  • Loose wiring
  • Disconnected wiring
  • Corroded wiring terminals
  • Corroded / faulty switch
Auto Technician and Writer at | Website

John Cunningham is an Automotive Technician and writer on Lawnmowerfixed.com. I've been a mechanic for over twenty years, I use my knowledge and experience to write "How to" articles that help fellow gear-heads with all aspects of mechanical repairs, from lawn mowers to classic cars.