Lawn Mowing Stalls When You Press On The Gas: Causes And Remedies

lawn mowers and gasoline trimmers. machines that perform not just mowing grass, but mowing it up to several times more than their counterparts with an electric motor. Once the lawn mowing or petrol trimmer stalls for a while, and the course of mowing the grass is immediately inhibited.

Diagnostic Features

A well-posed question is already half the answer. Significantly speed up the search for a solution is the fact. under what circumstances a gas trimmer or lawn mower stalls, namely:

  • immediately after the start;
  • when working idle for some time. after one or several minutes;
  • by pressing the gas button (or knob). or shortly after starting work at high, near-maximum speed;
  • under heavy load (for example, to cut bushes, mow thick and tall weeds);
  • when warming up in the cold. it heats up excessively (the lawn mower stalled due to overheating);
  • after opening the air damper.

Depending on which of the circumstances was clarified during the pre-diagnosis, the more specific cause of a mowing or trimmer malfunction is sought using the exclusion method.

Main reasons

The following reasons are possible: on which the lawn mowing or trimmer stalls when trying to re-start and continue the interrupted work:

  • engine malfunctions;
  • failure in the supply system of gasoline and oil;
  • damage to pipelines (capillaries, hoses, pipes);
  • malfunctions in the ignition system.

A general description of problems with a scythe or trimmer is not enough here. A clear and immediate repair, high-quality service is impossible without specifying the identified causes.

When gassing

You press the gas. and the trimmer stops working, does not develop speed. The following suggested causes are possible:

  • the carburetor setting is lost, which appears with an increasing load on the drive itself. after its long idle time or when working in extreme conditions;
  • fuel valve clogged with deposits;
  • the carburetor cable is weakened and sagged;
  • excessively stretched, possibly, and torn fuel hose;
  • the check valve (breather) clogged up with deposits. fuel does not enter the fuel tank.
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Important! Malfunctions in the carburetor itself impersonate the vibration of the lawn mowers.

With increasing speed

If the lawn mowing (or trimmer) stalled when adding engine speed. Check the device for the following symptoms:

  • clogging or sticking of the valve built into the gas tank cap;
  • violation of valve adjustment;
  • failure of pistons and cylinders due to vibration during the operation of the scythe or trimmer, accidental impacts directly in the grass mowing session;
  • violation of the air-fuel mixture;
  • excessive pumping of air into the motor;
  • cracking of the fuel intake hose, loosening of its connections.

When the air-fuel mixture is supplied in the right portions to the engine in an untimely manner. it burns the amount that has arrived since the last stall, and it stalls again.

When idling

Running a trimmer or lawn mowing at idle, you find that the device starts up. but stalls after working for, say, 5-10 minutes. The reasons here may be as follows:

  • blockage, violation of carburetor adjustment;
  • initially incorrect adjustment of the valve mechanism of the carburetor;
  • clogging of the air filter;
  • reduction in the speed of the gearbox (if any). the wrong ratio of the air-fuel mixture;
  • throttle clogging;
  • penetration of excess air into the fuel system;
  • fuel in the tank runs out (and oil in the tank if the engine is four-stroke).

Video: Lawn Mowing Stalls When You Press On The Gas: Causes And Remedies


If there are problems directly with the carburetor, the machine will stop both after a cold start and after starting on an engine that has already worked.

Right after the start

Mowing grass or trimmer immediately after the start is due to the following reasons:

  • imbalance of previously adjusted valves;
  • initially incorrect valve setting;
  • clogging with deposits of the fuel supply valve;
  • the hose is worn or loose.

Due to the violated algorithm of fuel injection, the lawn mowing or trimmer vibrate violently in operation.

In the process of warming up the engine

If the engine heats up too quickly, overheats. the lawn mowing or trimmer does not work as if in jerks. After which it stalls. The reason may be as follows:

  • boiling gasoline;
  • the ignition wire is damaged (poor insulation);
  • the coil in the ignition system noticeably burned out, inter-turn faults appeared.
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The same heating is observed when using a rotor (but not disk) gate.

When opening the choke

lawn mowing or trimmer stalls when raising the damper for the following reasons:

  • pumping up excess air due to a cracked fuel suction hose;
  • oil seals are worn;
  • improper functioning of the fuel and air dispenser when mixing them.

Stopping the lawn mowing in this case is immediate.

Troubleshooting Methods

By carburetor possible following works:

  • cleaning and adjusting the fuel supply valve;
  • similar operation with a valve that exhausts gases and vapors (after burning fuel);
  • replacing a weaker spring on the inlet valve;
  • restoration of tension of a carburetor cable;
  • replacing the fuel suction hose, checking and strengthening the loose connection;
  • change of a rotary shutter disk ;.
  • replacement of a faulty wire or ignition coil.

The list of ongoing work may also include cleaning nozzles (in a 4-stroke engine), replacing valve washers, gaskets in tank plugs, and so on.

Operation tips

It’s worth paying attention to a few recommendations for working with a lawn mowing or trimmer, extending the life of the device up to several times.

  • As soon as you notice that the lawn mowing or trimmer is vibrating. immediately stop working and check the serviceability, performance of specific parts.
  • Adjust the valves and check the operation of the pistons and cylinders, clean and change the nozzles, based on the requirements set forth in the user manual and recommendations of the service center wizards.
  • When air bubbles get into the system due to a broken fuel hose, apply gas. When gasoline with higher engine speeds is burned, gas bubbles will become smaller. But this is a temporary measure. Disassemble the unit as soon as possible and eliminate the cause of the suction of excess air.
  • Do not operate the unit in cold weather without warming the engine. it can often stall under load. The effect here is the same as in the case when the driver at 40 started the car and immediately drove off without waiting for the engine to warm up.
  • Do not leave the machine on the roadway. In the event of an accident, impact, it will immediately break, and this will make the purchase of a new unit a necessary measure. A car crashing into it will at best receive damage to the body and bumper.
  • Avoid working with lawn mowers or rain trimmers. In the worst case, ingress of water with air can cause the engine to explode. Similar situations arose with cars.
  • Do not use unchecked motor oils and greases. The mower warms up the engine more than the car itself would do. if the oil overheats, the oil will lose its lubricating properties. It will turn into a burnt out reagent. sticky, excessively viscous and viscous, like fuel oil. He will immediately stall (and shut off) the motor.
  • If the oil is old, previously drained from the tank of the machine or another (or the same) lawn mower (on a 4-stroke engine). defend it, filter to clean it of dirt and metal. But at the earliest opportunity, get fresh engine oil.
  • If the engine is two-stroke. observe the ratio of gasoline to oil. For compounds with mineral oils, this is approximately 34: 1, for semi-synthetics. 42: 1, for purely synthetic. 50: 1. Do not violate these proportions: “oiled” gasoline will not burn out and will quickly clog the engine, “unoiled” will accelerate the wear of its moving parts.
  • According to viscosity, oils with marking are classified as winter classes: SAE-0W / 5W / 10W / 15W / 20W / 25W. For the summer. SAE-20/30/40/50/60. For example, SAE 10W-40 is already multigrade oil (when the mower is in operation from spring to autumn inclusive). Be sure to check with the manufacturer exactly which oil is needed.
  • Always use high-quality gasoline that has passed all stages of purification from the manufacturer.
  • The recommended octane rating of gasoline is AI-92/95/98. The use of the 76th can lead to a lack of engine power, frequent stalling if you fill, for example, the 76th or 80th gasoline.
  • If you are not sure about the independent solution to the problems with the lawn mower (which does not pick up speed and often stalls), call the wizard or contact the service center for the repair of motorcycle and garden equipment. Specialists are not used to doing this work for you.