Disassembling The Trimmer

How to repair a trimmer starter How to repair a trimmer starter with your own hands. How to disassemble and assemble the starter, wind the spring and replace the cord.

The device and principle of operation of the starter on the trimmer

Gas engine. This is, in principle, the main part of lawn mowers.Its power lies in the range of 0.5-2.5 hp. The movement from it is transmitted to the shaft, which is inside the hollow rod, and then through a gearbox consisting of gears, already a fishing line or knife (working body).

Also, lawn mowers have the following elements:

  • Protective casing;
  • Lever;
  • Belt designed for the convenience of using the device;
  • A starter used to start a gasoline internal combustion engine.

All parts of the lawn mower are presented in the photo below.

The trimmer starter is the integral part that starts the engine. He is shown separately in the two photos below.

Starter mechanisms for various models of lawn mowers work on the same principle: during the start of the internal combustion engine, the protrusions marked with 1 in the photo above engage with the pawls 3. When the engine starts to work, they return to their previous position due to the influence of centrifugal force. The wires 2 also play a similar role.

The process of returning the elements of the mechanism to their original position occurs due to the presence of a spring wound around the axis. It unfolds when the rope is pulled. After releasing the cord, it is pulled in and wound up due to the coiling of the spring. During the start-up of the internal combustion engine, lawn mowers, the starting mechanism turns its shaft until it starts to work (starts).

Today, gasoline lawn mowers equip starter mechanisms of two types:

  • Manual;
  • Electric.

The first option is much more common.

The trimmer starter can operate without breakage for a long time. It is impossible to clearly indicate the period of uptime. Everything is determined by the initial quality of the device and compliance with the rules for handling it.

Starter assembly

The assembly of the starter unit is carried out in a number of stages:

  • The coil is turned over, setting it so that the spring bend fits exactly into the groove of the body, as in the photo below;
disassembling the trimmer
  • Two washers are laid, between which a spring is placed;
  • Put in place the cup with the antennae;
  • Tighten the screw (photos below).

When doing the above manipulations, it is imperative put two washers. If this is not done, then the spring will damage the plastic cup over time, and when it is pulled, wedging will begin. Because of this, there is a feeling as if the spring has flown off. To eliminate this drawback, you need to install this part of a greater length or an additional washer.

When such parts are not available, you can just unscrew the screw, and the starter assembly will start working without wedging. But this option is temporary. It is better to repair it with high quality as soon as possible.

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How to repair a trimmer starter

Petrol trimmer starter repair may be required at the most inopportune moment. In this case, the problem can be solved in two ways: replace the broken part or change the entire unit. The latter option is more expensive. To repair the device with your own hands, in most cases, you only need a screwdriver with the appropriate tip from the tools. Repair work does not take much time and does not require special knowledge. It is enough to know the device, the principle of operation, the nuances of assembling and disassembling the starter on the trimmer in order to achieve the desired positive result.

Causes of breakdowns and repair methods

If, for example, the tool stalls right after the factory or does not start at all, then pay attention to the ignition system:

  1. Remove the candle. If there are traces of a gasoline-oil mixture on it, then problem caused by carburetor adjustment. Violation of the cold start rules in the form of pumping fuel also leads to the throwing of the spark plug, and the poor quality of the gasoline used leaves a thick layer of black carbon. In these cases, this part will need to be replaced. If the spark plug is dry, then the malfunction is related to the fuel supply.
  2. The accumulation of dirt in the gas tank leads to clogged supply hose. Disconnect it. If the fuel does not flow, then the fault is a clogged filter or breather, which is cleaned with a needle, but the first one needs to be changed completely from time to time in order to avoid complications. It is advisable to do this every 3 months.
  3. In addition, gasoline trimmers often require replacement air filter, because if it gets clogged, the fuel mixture is not enriched enough.

Now a few recommendations that will help you fix the breakage and repair the tool yourself.

We will be glad if any of the proposed options suits you.

How to find a breakdown. Symptoms

Despite the fact that the gasoline trimmer is a complex device, some breakdowns can be found and easily fixed without the help of a service center or a technician.

Here are some ways to diagnose a breakdown at home:

  • First, check the spark, as without it there will be no ignition. If there is no spark, then the problem is in the spark plug, or in the ignition itself;
  • Also, if the plug is dry, then fuel supply repair or carburetor cleaning is probably needed;
  • If the spark plug is filled with fuel, wipe it dry and try to start the tool again;
  • If everything is in order, but the tool does not work, then the problem is most likely in the engine. If you do not know how to fix this part of the tool, then it is better to take the gasoline trimmer to the service.

Of course, we all want to save money on the services of a master, but do not forget that they take money for their unique knowledge and experience, which allows them to fix the trimmer with a 100% guarantee.

Major coil faults

Trimmer users and lawn mowers often face a problem with the semi-automatic mowing head. Coil malfunctions can be as follows:

  • The line does not lengthen automatically;
  • The cord spontaneously comes out of the reel.

How to remove the spool and replace the line

Trimmer owners, mostly beginners, find themselves in confusion, bordering on panic, when they need to change the cutting tool or line in the reel. Very often, when trying to unscrew the mowing head, users simply render it unusable, not suspecting that it is unscrewing in the opposite direction. To prevent this from happening, if you need to replace the tool, we recommend that you read the step-by-step instructions below.

  1. Stop the mowers engine or power off the trimmer before threading the spool to avoid injury from accidental starting rotation of the cutter.
  2. Unscrew the nozzle attached to gear shaft. To do this, the shaft must be fixed by aligning the holes on the washer and on the axle, and inserting a metal rod or screwdriver into them.
  3. Unscrew the nozzle. Be aware that the thread on the shaft is left-handed. Therefore, turn the trimmer coil to the right, that is, clockwise.
  4. Disassemble the mowing head. Most often, the head cover is attached on latches. To remove it, you will need to sink these latches into the case, pressing the edges of the cover. If your trimmer has a semi-automatic mowing head with a button on the bottom, then the disassembly of the attachment should be done carefully, since you can lose the spring, which sometimes flies out when the cover is removed.
  5. Cut off the required amount of line. Usually its length is 5 meters. Use a cord of the same diameter as indicated in the instructions for the tool. It is not recommended to exceed the maximum line diameter as this will result in increased engine stress and higher gas mileage.
  6. Find the midpoint of the line by folding it in half. You will have a loop.
  7. Coils are cut inside special grooves (there may be holes). Insert a loop of line into this slot.
  8. Wind the line around the spool by turning it counterclockwise. It is necessary to fill in the cord as evenly as possible, the turns should lie down without overlapping and with good tension. When the winding is complete, leave the free ends of the line about 20 cm long and fix them in the grooves on the sides of the reel.
  9. Assemble the mowing head. Before you finally assemble the attachment, be sure to insert spring and washer (if available). Place the spool in the body and thread the ends of the cord through the holes or eyelets.
  10. Put on the cover and secure it with the latches.
  11. Screw the adapter back onto the gearbox shaft, also securing it with a screwdriver. You will need to twist the trimmer coil to the left (counter-clockwise).
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Line does not lengthen automatically

If the line does not lengthen when you lightly hit the trimmer button on the ground, then the reasons for this may be the following.

Option 1. A bite has occurred, i.E. Clamping the cord between turns. This problem usually appears if the user has been winding the line on the reel unevenly, with intersecting turns, or winding it with insufficient tension. In the latter case, when the mowing head rotates at high speeds under the influence of centrifugal force, the cord begins to tighten, as a result of which inter-turn clamping of the fishing line is possible. To fix the problem, you will have to disassemble the coil on the trimmer and rewind the cord correctly, that is, in even turns with good tension.

Option 2. Too short ends protrude from the head. The line may not come out when hitting the ground if the ends sticking out of the head are not long enough (short). In this case, the centrifugal force is not enough to stretch the line. Therefore, it is required to stop the unit (turn off the engine or disconnect the trimmer from the mains) and pull the line manually, after pressing the button.

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Option 3. The line is soldered inside the mowing head. This causes the coil to lock and not spin when the button is pressed. Basically, this happens for several reasons: poor quality of the cord, overheating of the coil during prolonged operation of the unit, line hitting hard objects.

  1. In the first case, third-party cord can be made of low-quality and low-melting materials that cannot withstand mechanical and temperature stress. Therefore, you should give preference to “branded” lines.
  2. But, if you nevertheless purchased a fishing line of unknown quality, and it is often soldered during operation, then you can follow the example of some users who, after threading the cord into a reel, wet it either silicone grease (from a spray can), or mineral oil. This procedure greatly reduces the likelihood of the coils of the fishing line being soldered together.
  3. Also, the line can be soldered if it hits a hard object (stone, fence, dry branch, etc.) during mowing. As a result, it stretches slightly and is pulled back into the head at high speed. From friction, the cord heats up, and its turns stick together. The only thing that can be done to eliminate this malfunction is to open the trimmer coil and rewind the line.

Disassembling the trimmer

We start to disassemble the electric trimmer:

First, we disconnect the two connected trimmer halves, the control handle from the contact connection with the electric motor itself.

Two photographs \ photo # 2, photo # 3 \ show the sequence of disconnecting the electric motor from the control handle.

Next, we need to check, perform diagnostics. Control knobs \ photo №4 \. We disassemble this part and carry out diagnostics for individual electrical connections \ photo No. 5 \.

Diagnostics with a multimeter

For such a check, we need a digital multimeter. You can also use a pointer multimeter or a device such as an ohmmeter. There is no difference at all.

We set the digital multimeter to the measurement range of the least resistance, connect the probes of the device to the socket of the detachable connection \ output contacts of the electric motor \. The device in this example \ photo # 10 \ shows one in our case. The display reading of the device means a break in the electric motor circuit.

It is necessary to further look at what may be the cause of the malfunction, and of course we will need to disassemble the two connected parts of the case, where the electric motor circuit is directly located.

Electric trimmer diagram

Line trimmer wiring diagram, simple, consisting of:

  • Potentiometer, motor control speed;
  • Capacitor

And directly the electric motor itself.

The cause of the malfunction at the beginning during a visual inspection was incomprehensible, the trimmer had to be completely disassembled to determine the true cause of the breakdown.