Husqvarna Mower Dies When Blades Engaged – How To Fix

If your Husqvarna mower dies while the blades are actively engaged, you’d first want to figure out the reason for the malfunction because you will only find the right fix if you know that the problem is. For instance, if the mower’s grass box isn’t fully closed, the safety sensor to stay open, killing the mower’s engine while the blades are still engaged. In such cases, you’d fix the problem by checking the box to ensure that it’s closed and that there is no glass jamming it. The engine could also die with the blades still engaged in case of misalignment of the glass box, loose sensor wiring, a faulty sensor, bad gas, and in other cases, a dirty or faulty carburetor could be behind the dead mower.

Below, we look at the main reasons why the mower’s engine could die with the blades still engaged.

Husqvarna Mower Dies When Blades Engaged – How To Fix

Causes of Dead Engine with Blades engaged	Remedies
Open Grass box	Remove anything that could be jamming the box
Misalignment of the Grass Box	Straighten the support arms
Loose Grass Bag Sensor	Check and fix/ replace connectors, replace sensors
Damaged Grass Bag sensor	Replace sensor with new one
It’s running on bad gas	Drain stale gas, put in fresh gas
Dirty Carburetor	Clean carburetor, Use Fuel Stabilizer, buy new carburetor
Clogged up fuel cap	Replace the fuel cap
Defective spark plugs	Replace plugs
Poorly-routed or broken drive belt	Re-route or replace the drive belt

Grass Box is open (Partially)

As expected, your Husqvarna lawn mower comes fitted with numerous security features. The sensors are attached to different components of the mower, and their positions are relayed on the main control panel. Now, if you follow the setup and fix the elements of the mower correctly, the engine will start and continue running.

Unfortunately, the grass box’s sensors are often overlooked, even though you can spot any issues with it from the control panel. This sensor is placed at the mower’s rear, in between the grass bag and the mower. The role of this sensor is to tell the engine that the box’s control panel is safe, and it’s, therefore, safe to engage the blade. Any mishap in this communication line will result in the engine dying, even with the blades still engaged. If this happens, the first thing to do would be to check to ensure that there is no jamming or other obstacles stopping the box from closing fully.

Remove the wiring from the sensor’s back, then connect the wires to bypass the sensor. You could use a car fuse or any other type of wire around.

If there is no jamming, the problem could be any of the ones listed below:

Grass Bag’s Misalignment

Often, the glass bag is misaligned when the mower is accidentally reversed, and it catches something unexpected, and if the grass bag support arms are bent out of shape, which causes the grass bag’s frame of the gasbag sensor, killing the engine.

You can fix this by straightening out the support arms, ensuring a better fit for the grass bag. Unfortunately, straightening out the grass bag is a tedious job, yet you’d have to remove the grass clumpings and trailings.

Loose Grass Bag Sensor

Sometimes, the problem could be something as simple as a loose sensor. In such cases, you’d have to focus on the wiring to fix the problem.

Check the sensor’s rear for a wiring connector – this could be a single block or, in other cases, two push-on connectors. Check if these connectors are fully connected because they come to loose sometimes. There could be damage to the wiring system too. So, remove the connectors to check for corrosion – corrosion prevents proper relaying of signals to the control panel, so if there is corrosion, you’d want to replace the connectors.

The terminals could be dirty, and you’d have to clean them out using a professional contact cleaner then apply some silicone grease to prevent moisture from getting in.

To ensure that the sensor’s wiring is working well, get a wiring repair kit in your nearest auto parts store. The kit must have new push-on connectors, tape, and joiners, or soldering iron.

Damaged Grass Bag Sensor

Though an uncommon issue with the Husqvarna mowers because the company makes long-lasting sensors that really work well, there are cases where the sensor will be troublesome. Just to be sure, check the sensor’s output and function using a voltmeter. Run tests on each of the sensor’s terminals; if there is no reading with the sensor closed by your hand, then it’s faulty. The only remedy for this is replacing the sensor – just release the old sensor and push the new sensor’s plastic wings in before pushing in the sensor starting from its wiring end.

Note that a well-functioning sensor will read close to 0 ohms, and this shouldn’t be replaced.

It’s running on bad gas

Stale gas is not as combustible, and it will stop the engine, affecting the function of the blades while they are engaged. Bad gas could also stall the engine when mowing steep areas.

This problem is easy to fix, though – just drain out the old gas with fresh gas. And if you store your more for more than a few months, use a gas stabilizer.

Dirty Carburetor

While your lawnmower’s engine is quite forgiving and simple, the carburetor is none of these things, and it must be finely tuned, with the slightest changes in the fuel/ air balance affecting how the engine runs. Now, the carburetor has two main functions – to mix gas and air in a 14:7:1 ratio and also to supply just the right amount of the mixed gas to the engine, depending on the engine’s load demands. Unfortunately, dirt in any component will result in fuel starvation, which kills the engine, even with the blades engaged. The only way to remedy this problem is to clean out the carburetor and change the gas. A clean carburetor and fresh gas will keep the engine running safely.

In the case of a restricted carburetor, you’d also have to use a fuel stabilizer. If all the remedies given here don’t work, you may have to buy and install a new carburetor.

The other reasons why the mower would die while the blades are still engaged are as follows:

Clogged up fuel cap – replace the fuel cap

Defective spark plugs – this can be fixed by replacing the defective spark plug.

Poorly-routed or broken drive belt – the drive belt is an essential part of the engine, and it drives all the important parts of the mower like the air pump. It has to spin freely on the pulley and the belt tensioner for proper blade engagement. To fix this problem, you’d have to re-route or replace the belt.

Conclusion

If your Husqvarna mower dies while the blades are still engaged, it often means that there is some form of mechanical or physical damage or fault. Fix the problem, and you won’t have any other issues with the engine or blades. Just make sure to follow the safety instructions provided.

FAQs

1. What causes 4-stroke engines to backfire?

The most common reason why this would happen is if there is a bad plug. But it isn’t the only cause of the problem. Other potential problems include the wrong type of plug, broken shear key, faulty carburetor, leakage in the intake vacuum, stale gas, the wrong gas type, andbuild-up of carbon in the cylinder.

2. What causes John Deere mowers to die with the blades still engaged?

The most common reason for this is that the grass box isn’t closed fully, which forces the safety sensor to shut down the engine.