Why Won’t My Lawnmower Start?

With the main mowing season running from March until October, and it being recommended to mow your lawn on at least a weekly basis, your lawnmower understandably comes under a lot of pressure, wear and tear.

As a result faults can arise. One such problem, which is more common than you may think, is the lawnmower not starting. Thankfully, whether you have a petrol or electric lawnmower, rectifying such an issue can often be relatively easy.

Electric Lawnmower Not Starting:

Electric lawnmowers are common in households where there’s a small /medium lawn. But, despite only cutting small areas of turf, they can still suffer from starting issues – and this is usually caused by one of five things.

• Thermal Cut-Out Activated (if fitted) – the thermal cut out on your lawnmower protects the motor, and will be activated if a) the blade becomes jammed (see below) or b) the motor is overloaded. When the thermal cut-out is activated, your mower will not start, but such an issue can be easily resolved, by doing one of two things.1) Wait a couple of minutes to allow the lawnmower to reset itself
  2) Manually reset it (find out how to do this by checking the manufacturer’s manual)
  
• No Power – should your lawnmower not start the moment you take it from the shed / garage, it’s likely it has no power/is getting no power due to one of three reasons.1) Fault with the fuse in the plug – you can test to see if the fuse is the issue in your plug by plugging another electrical appliance into the socket. If this works, it’s a clear indication the fault is with the fuse. For confirmation, test the fuse with a multimeter – and you can find out how to do this by watching the video below.

2) Damaged electric cable – a damaged electrical cable on your lawnmower can only stop your lawnmower from starting, but it also has the potential to be a serious risk. In the case of such a fault, you will need to replace the cable on your lawnmower immediately.

3) Fault with mains power – if you suspect there’s a fault with the mains power, we recommend you try another plug in the home first, if there is still no power check the fuse board. If there isn’t any power, you may need to contact a qualified engineer to check your electrics.

• Blades Jammed – if your lawnmower blades have become jammed due to a build up of dirt, your lawnmower although may start, is likely to make a loud humming noise before cutting out, and this is because the thermal cut out has been activated.If your blades are jammed, switch off the lawnmower and unplug it before thoroughly cleaning the underside, making sure all grass debris is removed.
• Faulty On / Off Switch – difficulty starting your lawnmower could be caused by a faulty on/off switch, and if this is the case you will need to replace the switch. Before carrying out such a repair, make sure the mower is unplugged and then remove the switch housing from the lawnmower handle.Once the switch housing is removed, undo the screws holding the casing together and split the housing in half – this will give you access to the on/off switch.

  We recommend before you take the switch out of its casing, to make a note of the wires going into it. You may also need to use pliers to pull the wires out. Once the wires have been taken out, all that is left to do is reverse the steps to fit the new switch.

• Motor Assembly Fault – if the motor assembly on your lawnmower has become faulty you will need to replace it. Carrying out such a repair will require time and patience, but there is no reason why you cannot do it yourself, by watching our “How To” video below.

Petrol Lawnmower Not Starting:

Petrol lawnmowers naturally produce more power, and are ideal for lawns which are over 200m or where cutting the lawn is difficult due to uneven surfaces. However, as with their electric counterparts they can sometimes fail to start, due to a number of reasons including:

• No Fuel / Dirty Fuel – one of the primary reasons for a petrol lawnmower failing to start, particularly at the start of the mowing season, is due to there being no fuel or dirty fuel in it.Rectifying the issue of no fuel is straight forward and self explanatory. When it comes to dirty/stale fuel, however, it is a bit more difficult.

  If the lawnmower has sat idle throughout the winter months with fuel left in it, there’s a chance the fuel has become dirty/stale and will need replacing. Ideally, you should empty your mower of fuel before placing it away for winter as petrol residue loses its combustibility over time.

  To drain the fuel from your lawnmower, you will need to drain both the main fuel reservoir, by uncoupling the fuel line and draining the fluid into a bowl. Then press the release valve on the carburettor (if fitted), to drain this area too. Once you’ve done this, you can top it up with new petrol.

• Fuel Valve Turned Off – you may not have noticed, but your lawnmower has a fuel valve. The role of this is to prevent petrol from leaving the fuel tank and ending up in your lawnmower’s engine.You’ll usually find the valve at the base of the fuel tank, where the fuel line is connected, and it’s a good idea to check that this is in the correct position, if your lawnmower isn’t starting.
• No Spark – if there isn’t a spark, there may be a fault with the spark plug. It could be that it needs cleaning, which is relatively straightforward. Simply take the spark plug out and give it a once over. If it’s looking a bit dirty with sooting, give it a clean with a wire brush before getting between the two electrodes with fine sandpaper.If cleaning the spark plug doesn’t resolve the issue, you’ll most likely need to replace the part – and this is as simple as purchasing a new one and fitting it in place, before tightening it up.
• Blocked Carburettor – unfortunately if your carburettor appears blocked, it is easier to contact a qualified engineer to carry out the repair and get the lawnmower up and running.

For more advice on what to look for if your lawnmower won’t start, or to find out how to carry out the repairs mentioned in this section, we recommend you watch the following eSpares video.

Steps To Reduce Faults:

Prevention is always better than cure, and there are a number of steps which you can take to prevent your lawnmower developing faults. The best preventative step is to carry out regular maintenance.

Carrying out regular maintenance, such as checking the lawnmower blade, cables and other components, as well as cleaning the underside of your lawnmower and this will help reduce the risk of faults occurring.

Along with carrying out regular maintenance after each use, it’s also advisable to carry out thorough maintenance at the end of the cutting season. This involves:

• Rubbing each moving part with an oily rag to prevent rusting
• Emptying the petrol from petrol mowers – if left for long periods of time, petrol can go off and result in issues starting your mower in the future
• Examining any cables for any splits or damage and replacing where necessary
• Cleaning all parts of your mower, including the air vents, undercarriage and blades

Following the advice outlined above will help you to make the most out of your lawnmower throughout the entire mowing season and beyond, helping you to achieve a luscious lawn all year round. Should you require any spare parts for your lawnmower, you’ll find them via the eSpares website.

Tags: Lawnmower Blades, Lawnmower Faults