How to Wind a Spring on a Stihl Lawn Mower Starter
To quickly start any chainsaw, a starter is required. With accelerated scrolling of the crankshaft of the tool, the fuel-air mixture supplied to the engine is compressed and its subsequent ignition. Therefore, the normal operation of the starter for a chainsaw determines the operability of the entire mechanism.
The most common tool breakdowns include the following:
- problems in the ignition system;
- stopping the operation of the chainsaw in the process of cutting;
- power loss during operation;
- wear of some structural elements of the chainsaw (brake band, drive sprockets, anti-vibration parts);
- problems in the fuel supply system;
- malfunctions associated with the starter.
In addition, it is necessary to carry out a visual inspection of the chainsaw before starting work and preventive measures. These include chain lubrication, control of the amount of fuel mixture, as well as the presence of the required amount of oil.
Unscrew the spark plug to check its condition.
Each of the faults is eliminated by its technology. So, for example, repair of the fuel system of a chainsaw should begin with an inspection of the appropriate filter. After that, check the carburetor regulation, which is carried out using screws. Clearances must be set in strict accordance with the manufacturer’s instructions, which must be included with the chainsaw. To repair the ignition system include inspections of candles. If a strong deposit is detected, a change in the gap or other visible damage occurs, this element must be replaced.
How to repair a chainsaw starter with your own hands
Presented is the repair of a chainsaw starter after a break in the starter cord. Without a starter cord, the chainsaw becomes completely inoperative; there is no other way to start the tool. The repair was examined using the Partner P350S chainsaw as an example; a tricky reliable start of this saw requires a minimum of 4-5 times pulling the starter cord in order for the saw to work, therefore, probably, the first malfunction was a break in the cord. The cord does not tear immediately, the protective stocking of the cord threads breaks off at first and prevents the saw from starting. It is better not to wait for all the threads to break and fix the cord in advance. There is no need to invent anything, repair should not cause difficulties, but exact observance of the assembly conditions is necessary. A step-by-step instruction with a diagram of actions with photos and videos is given below.
1. Unscrew the three screws securing the starter cover. The included candle wrench with a straight screwdriver is suitable for this process, but to speed up the work it is better to use a normal tool.
2. Remove the starter. The chainsaw is equipped with a soft start mechanism, it is located above the reel with a cord.
3. Unscrew the screw securing the soft starter and starter coil. Caution do not lose the puck!
4. We remove the soft-start mechanism.
5. We take out the cord winding coil.
6. We prepare a cord suitable for the diameter of 1.2-1.3 meters in length. For repair used kapron clothesline :).
7. We melt the ends of the rope over a fire so as not to dissolve.
8. Tied at one end of a complex knot. The assembly is required to be large in diameter, but should not protrude when mounted on a coil.
9. We fill the cord into the hole of the coil. Do not wrap the cord!
10. Insert the coil into place. Installation error may be made here. The coil has two slots, in one of which a spiral spring hook should fall. Install the coil so that it snaps firmly into place and the hook snaps into place. It is checked by turning the coil clockwise to determine the occurrence of a return force.
Video: How to Wind a Spring on a Stihl Lawn Mower Starter
11. Install the soft starter. The protrusion of the mechanism should stand in the recess of the coil.
12. We fasten the fixing screw with the washer.
13. We fill the second end of the cord into the outlet.
Installing the soft starter
14. Fill the cord into the start handle. We tie a large knot at the end of the rope. With a small knot, there is a chance of the rope slipping and the entire cord is wrapped in the starter and in order to get it out the starter will need to be removed again. Check the reliability of the node. Look at the photo.
Cord in trigger handle
15. The most important moment! We release the loop of the cord inside the starter and begin to rotate the starter mechanism clockwise without winding the cord! For this saw, you must make a minimum of five turns. We fix the coil by hand. We pull the loop by the handle outward. Holding the cord and mechanism, we allow the cord to be wound on a reel. Watch a video.
16. Check the operation of the mechanism.
17. Install the starter in place and fasten it with three screws. Repair done.
Repairing a tattered or damaged cord using step-by-step instructions takes 15 minutes, which is much faster and cheaper than contacting a service center.
If the instructions helped you, let me know in the comments.
Chainsaw starter diagnostics
Due to the long-term operation of the chainsaw, the trigger mechanism becomes unusable. After one or several jerks, the crankshaft does not rotate when pulling the starter rope. This problem can be caused by the following reasons:
- cracked or broken drive pulley;
- the chainsaw starter spring burst;
- a gust of rope launch.
Before starting work on the diagnosis and repair of the start-up mechanism, it is necessary to prepare the necessary tools and accessories that will significantly reduce the time for operations. These include:
- A set of bench screwdrivers and a specialized set of proprietary tools included in the scope of supply of the chainsaw.
- Strong cord to replace a worn starter rope.
Chainsaw starter spring
At the first stage of repair of the chainsaw starter, it is necessary to identify the nature of the problem. To do this, remove the side cover from the side of the start mechanism, while unscrewing only a few screws. Depending on the manufacturer, this operation will require a specialized or conventional locksmith screwdriver.
Next, we inspect the inside of the protective casing. In the absence of cracks and chips of plastic, we proceed directly to the diagnosis of the launch site. We unscrew the central bolt of the starter and dismantle the spring. No cracks or gusts should be observed on its surface. It is problematic to choose a spring similar in strength and number of turns on your own, therefore the help of specialized centers will be required.
After removing the clamp and the starter spring of the chainsaw, a pulley with a wound cord is accessible for dismantling. The integrity of the rope indicates that it is necessary to carefully review each of the details of the trigger mechanism.
Device and principle of operation
The work of the starter is as follows: on the case of the chainsaw there is a handle through which a special cable passes, pulling and hooking the drum of the ratchet mechanism with a sharp pull. In this case, the movement is transmitted to the drum with splines on the shaft.
At this time, the crankshaft makes several full revolutions, as a result of which the working mixture is compressed between the cylinder head and piston. If you release the handle, then the contact between the splines and the ratchet will be lost, as a result of which the shaft will simply stop!
The larger the engine capacity of the chainsaw, the more fuel-air mixture will be required for further ignition. Based on this, as a rule, more jerks are required for starting high-power saws for the starting cable. For greater convenience and to accelerate the return of the drum, manufacturers began to use forceful return springs from elastic steels.
The simplification of starting a chainsaw is achieved due to the following factors:
- The presence in the design of some models of chainsaws (for example, in Maxcut, Partner models of the S line, etc.) of a special pump that guarantees timely pumping of the fuel mixture.
- Mounting an additional spring, which provides easier unwinding of the crankshaft when the cable is displaced.
- Due to the preliminary enrichment of the mixture through the corresponding valve in the carburetor body.
- Placements automatic decompression valve, which will reduce the working pressure inside the cylinder.