The Lawn Mower Does Not Start Well

15th July 2020

The petrol lawn mower will not start The petrol lawn mower will not start. Why?

The lawn mower won’t start

If at the first start, your new lawn mower refuses to start, try the following: based on the outside air temperature, set the appropriate position of the air damper (at temperatures less than 30 ° C. “damper closed”, over 30 ° C. Half-closed position), then pump into the carburetor fuel and gently, but rather sharply, pull the starter handle until you feel some resistance. Repeat these steps in the same sequence several times. A brand new instrument must start. If this finally happened, you can safely start working by opening the damper completely beforehand.

If the mower is no longer new, then it is necessary to start its inspection from the gas tank. If the device has not been in operation for a long time, then it is necessary to drain the old gasoline, which has the feature of “running out”, i.E. Lose its octane properties, and refill with fresh fuel mixture. The gasoline / fuel ratio, as well as the required grades, are usually indicated in the operating instructions for the tool.

Now you need to check the spark plug. Either the problem is in it itself, or in the fuel system. The candle must be carefully unscrewed and its condition evaluated. If the candle is heavily flooded or there is black carbon on it, then it must be removed, cleaned and dried. Drain the excess fuel, if any, from the spark plug holes, drain the cylinder itself, then screw in the dried or, even more desirable, a completely new plug. If the plug was completely dry initially, you need to look for a problem in the fuel supply system. Check the fuel filter first. To do this, disconnect the suction hose and remove the dirty filter from it, clean it and reinstall it, or replace it with a new one. If this does not help, you should contact the service center specialists.

The petrol lawn mower will not start. Why?

Will not start after winter

In this case, you just need to drain the old and, possibly, even frozen fuel and fill in the freshly prepared mixture. Then you need to perform the same manipulations as during the first start of the lawn mower.

The lawn mower won’t start

If at the first start, your new lawn mower refuses to start, try the following: based on the outside air temperature, set the appropriate position of the air damper (at temperatures less than 30 ° C. “damper closed”, over 30 ° C. Half-closed position), then pump into the carburetor fuel and gently, but rather sharply, pull the starter handle until you feel some resistance. Repeat these steps in the same sequence several times. A brand new instrument must start. If this finally happened, you can safely start working by opening the damper completely beforehand.

If the mower is no longer new, then it is necessary to start its inspection from the gas tank. If the device has not been in operation for a long time, then it is necessary to drain the old gasoline, which has the feature of “running out”, i.E. Lose its octane properties, and refill with fresh fuel mixture. The gasoline / fuel ratio, as well as the required grades, are usually indicated in the operating instructions for the tool.

Electrical faults:

The reason that the electric lawnmower stalls immediately after starting or during operation may be a break in the supply cable or a loss of power in the network.
The electric trimmer gets very hot and can smoke. Overheating of the engine and its probable failure can be caused by too long operation or overload, which occurs due to blocking of the cutting elements by any foreign objects. Sparking and fumes can be caused by improperly selected or incorrectly positioned brushes.
One of the reasons your electric lawnmower won’t start is if the control button is faulty.

The most frequent breakdowns of a lawn mower

Malfunctions of gasoline vehicles can also be roughly divided into two main types. Engine breakdowns and mechanical problems.

The lawn mower starts and stalls. What to do?

1. There is a spark, and everything seems to be normal, but the mower will not start, in such cases you should check the air inlet valve to the fuel tank. A clogged valve leads to the creation of a vacuum in the tank, in which the carburetor does not receive enough gasoline, so the lawn mower will start, but then stall. To exclude this reason, you need to clean the valve and try to start the lawn mower with the tank cap not completely twisted.
2. If this does not start the mower, remove and clean the fuel filter and check all carburetor parts, then try starting. The lawn mower will not start again, the air filter is disconnected, try to start without it, if the mower starts up, the reason is in the air filter, replace it.

The lawn mower will not start, the spark is gone

The loss of a spark entails checking the contacts and the correctness of the gap between them, the conducting wires to the candle and the candle itself.
The way to check the spark is to unscrew the candle, connect the wire to it, put the candle sideways to the motor casing and pull the starter several times as if starting the lawn mower, while looking at the coal and the contact of the candle, a spark should run between them.
If there is no spark, take a new candle, follow the same procedure, if the spark cannot be traced, then there is a problem in the wire or contacts, it is better to replace them.

The lawn mower will not start, or will start but stalls. What is the reason?

To understand this, you need to know the principle of operation of the unit as a whole. It also happens that, just bought, a new saw does not start, and it starts running around the service centers, in such cases it is recommended:

Carefully read the instruction manual;
to study in detail the method of first starting and running in lawn mowers;
try to understand how the product works;
how gasoline is pumped up and so on.

Causes of malfunctioning lawn mowers:

The quality of gasoline is poor;
incorrect proportion of gasoline and oil;
clogging of the fine filter;
the spark was gone.

Lawn mowers filter diagnostics

Another reason why the gasoline scythe stalls is the air filter. To eliminate it, try removing the filter and starting the trimmer without it. If possible, then you will have to change the air filter to a new one, or at least blow through and thoroughly clean the old one.

The petrol trimmer may not start if the fuel filter is dirty. This is the next step in our algorithm. Here we check the condition of the filter element and, if necessary, replace it with a new one. When replacing, try not to leave the suction pipe completely without a filter, this is prohibited by any operating instructions. Haste can turn into repairing the engine piston group.

Breather and exhaust port

Often, “gentle” branded lawn mowers do not start and stall due to a dirty breather. The main function of this element is to equalize the pressure in the gas tank. When this unit becomes clogged, a vacuum is created in the tank, which prevents the supply of fuel. You can eliminate the malfunction by cleaning the breather. You can use a regular needle for cleaning.

Normal operation of streamers with internal combustion engines can be disrupted due to dirt entering the exhaust channel or a clogged silencer mesh. There is such a problem on older generation models. The issue can be resolved by traditional cleaning and removal of the anti-spark grid.

Complex reasons for lawn mowers failure

If the step-by-step troubleshooting algorithm does not work, and your scythe still does not start or stalls, it is worth inspecting the carburetor and the engine itself. A clogged carburetor can be one of the reasons for erratic tool performance. There are three main problems here:

Clogged ducts or nozzles. All this is cleaned by special washes or blown by a powerful jet of compressed air from the compressor. Do not use needles and wires, as the bore may be damaged;
Worn carburetor gasket. Exit. Replacement of a failed gasket;
Violation of tightness. To check this indicator, you can use an ordinary household tonometer, replacing it with a suitable pressure gauge. Watch the readings: if they do not change, everything is fine, and if the pressure starts to drop, then some part of the carburetor is faulty. We’ll have to find it and replace it with a new one.

If everything is in order with the carburetor, then the petrol trimmer may not start due to wear of the piston group. If chips, scratches or scuffs are found, the piston or cylinder should be replaced. Piston rings are subject to mandatory checks. A small backlash of the piston when rocking the connecting rod indicates that it is time to change the rings. It is best to entrust this procedure to the specialists of the service center.

Blades not adjusted correctly

This can be seen from the uneven surface of the lawn. Unplug the mower and wear protective gloves before making adjustments.

The gap between the cylinder and the knives should be uniform in all areas and not exceed the thickness of a sheet of office paper. Even the same paper is used to adjust the gaps. It is inserted between the cylinder and the knife, after which the drum rotates. Adjust the knives until the paper is cut evenly at any point on the knife.

The lawn mower is not picking up speed

The reason may be such malfunctions:

It is necessary to inspect the muffler. It may be clogged;
The grass is wrapped around the shaft and from this does not twist the knife, as shown in the photo;
Rust on the mechanism and parts;

If the mower does not work at full capacity, it is necessary to disassemble and clean the mechanism.

The lawn mower will not start

If the engine will not start, check the position of the choke. If the air temperature exceeds 30 ° C, set the middle position;
With prolonged operation of equipment, it is necessary to take breaks for 5 minutes to avoid overheating of the engine;
It is necessary to check if gasoline has hit the spark plug;
If the gasoline in the tank is stagnant, it is worth changing it to a new one;
It is necessary to check whether the filter passes air well, if necessary, rinse it;
You can pump fuel into the carburetor using a primer.

If the mower does not drive, the drive belt should be checked. It may be worn out and needs to be replaced.

What to do if the petrol lawn mower won’t start?

The most important point when using any equipment is to comply with the basic rules of operation and its timely maintenance. This approach will ensure that your petrol lawn mower is working properly and for a long time. Still, sometimes unforeseen situations happen, and the device for some reason does not want to start. In our article we will tell you about the possible causes and solutions to this problem.

Faults that you can correct yourself

When your petrol lawnmower will not start, the first step is to check that there is fuel in the tank. If it is missing. Top up to the desired level. Often, when the device is not used for a long time, gasoline “runs out”, so it must be completely drained and refilled with new. This procedure must be done carefully so that fuel does not get onto the engine, as this can lead to ignition in the future (when the engine heats up). Which gasoline is better to use, you can find out from the technical passport of the device.

In order for the unit to start, you need to pump fuel with a primer (if available in this model) into the carburetor and set the maximum speed. You need to start the technique carefully. The starter cord must be smoothly pulled out until it stops, and then pull it towards you with one even sharp movement.

A problem can occur if the air damper is not correctly positioned during the first start. Depending on the air temperature, it is completely closed or set to the middle position (above 30 C). Then it must be fully opened.

Check the air filter for dirt. To do this, turn off the machine and disconnect the wire from the spark plug. Unscrew the cover and remove the filter. Wash it with gasoline and dry it thoroughly, or just put a new one. Remember that it is recommended to change the air filter after every 25 hours of operation.

Another reason your petrol lawnmower won’t start could be a faulty spark plug. Perhaps she was just flooded with fuel. In this case, unscrew it, clean it and check for a spark. It may not be present when the spark plug is filled with fuel. Move choke control handle (if equipped) to the CLOSED position and start the engine. If this does not help, it is better to seek help from a specialist.

Try to constantly inspect the underside of the unit, as any damage to it may cause the engine to stall.

If your petrol lawn mower started up normally but stopped working almost immediately, it is likely that the crankshaft or piston is stuck. Another reason may be insufficient oil in the crankcase. We recommend manually moving these parts and checking the oil level with a special dipstick, you may be able to correct this problem.

However, remember that the replacement and repair of all faulty components and elements should be entrusted to professionals from authorized service centers. Never do it yourself.

If you want to talk with a specialist and get advice on the issue that has arisen, call us by phone: 7 (495) 135-29-39 every day from 10.00 to 20.00. We will provide all the information you need.

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