When your loyal garden assistant stops starting or loses power, the first thing that comes to mind is to replace the power unit. Engine to benzotrimmer It's the heart of the machine, and it's the quality of the grass and weeds that you're putting on your site that depends on the quality of the work, and many garden appliance owners are faced with a situation where it's not economically feasible to repair an old engine, and the only way out is to install a new power plant.
But the process of replacing or matching a machine is not as simple as it seems at first glance. There are many nuances related to the type of attachment, cylinder volume and features of centrifugal clutch. In this article, we will discuss in detail how to correctly identify a malfunction, choose the right model and correctly install it so that your tool works again as a new one.
You should not immediately run to the store for a new trimmer, if the old unit is reliable and easy to use. combustion-engine You can restore or replace it with a more modern and powerful analogue, while retaining the bar and gearbox, which will save a significant amount of money and extend the life of time-tested equipment.
Typical signs of trimmer engine failure
Before you make a decision to buy a new unit, you need to accurately diagnose the problem. Often symptoms that seem fatal are solved by small adjustments. However, if you see a loss of tightness of the crankcase or a critical wear of the cylinder-piston group, then you can see that the problem is very difficult to solve. engine-change It becomes inevitable.
One of the main indicators of the condition of the engine is the color and nature of the exhaust gases, as well as the behavior of the tool under load. If the trimmer dies when adding gas or smokes in blue, this can indicate serious problems with lubrication or combustion of fuel.
- 🔥 The engine does not start even after repeated attempts and checking the spark plug.
- 💨 From the muffler pours thick black or blue smoke, indicating the burning of oil.
- 📉 Noticeable loss of power: the mower knits even in soft grass.
- 🔊 The appearance of extraneous knocking, grinding or metal ringing inside the crankcase.
⚠️ Attention: If you hear a piston hitting the cylinder (called a skirt bang), further operation is strictly prohibited, which will lead to complete destruction of the engine and possible jamming of the crankshaft.
You should also pay attention to compression. Low cylinder pressure often indicates rings or bullies on the cylinder walls. powertrainIt is important to consider that two-stroke motors have a limited resource, and once this resource is developed, their efficiency decreases irreversibly.
Criteria for selecting a new engine to replace
Choosing the right engine is not just about buying the first option with the same volume. Landing dimensions And the type of shaft is critical to compatibility with your trimmer bar, and a mistake at this point will cause the new engine to simply not stand in place or be able to transfer torque to the knife/fishblock.
First of all, you need to determine the diameter of the shaft and the number of slits. Most household trimmers use shafts with a diameter of 7 mm or 8 mm, but the pitch of the slits can vary. It is also important to consider the direction of rotation: standard engines rotate clockwise (when viewed from the side of the crankshaft), but there are also reverse models.
Power also matters, but it has to match the strength of the gearbox, and if you put a motor that's too powerful on a weak gearbox, you'll get a rapid wear and tear or breakage of the gears. petrol-engineAdhere to the specifications recommended by the manufacturer of your trimmer model, or choose analogues with a small power reserve, but within reasonable limits.
- 📏 Shaft diameter: most often 7 mm, 8 mm or 10 mm (for professional models).
- ⚙️ Type of fastening: The distance between the fastening holes on the flange must be the same.
- 💨 Cylinder volume: must correspond to the trimmer class (household, semi-professional, professional).
⚠️ Attention: Never ignore the type of carburetor. Engines can come with different carburetor models (such as Walbro, Zama or Chinese counterparts), and the fuel mix can be adjusted differently.
The ignition system deserves special attention. Modern engines are often equipped with electronic ignition without contacts, which increases the reliability and stability of spark formation. When choosing, check for a candle in the kit, as sometimes manufacturers save on this element.
Technical specifications and compatibility of models
To make it easier to find a suitable model, you need to focus on basic technical parameters. Stihl, Husqvarna, Champion And there are many Chinese analogs, and understanding the labels will help you to avoid confusion.
An important parameter is the working volume, which directly affects the torque. For suburban needs, a volume of 33-40 cubic meters is usually enough, while for hay harvesting or working with a thick weed, 52 cubic meters are better suited.
| Parameter | Household class | Semi-professional | Professional |
|---|---|---|---|
| Engine capacity | 25 - 33 cc. | 40 - 45 cc. | 52 cc and above |
| Power (hp) | 0.8 - 1.2 | 1.3 - 1.7 | 1.8 - 2.5+ |
| Engine weight | 2.5 kg | 2.5 - 3.5 kg | 3.5 - 4.5 kg |
| Motorwatch resource | 300 - 500 | 600 - 900 | 1000+ |
The interoperability of the mounting holes is critical, and the distance between the mounting holes of the engine and the rod should be identical, and if the new motor has a different mounting pattern, you'll have to do the plumbing work of drilling new holes or making a transition plate, which is not always safe.
Can I get a bigger engine?
Theoretically, it can, but it requires replacing the centrifugal clutch and perhaps the gearbox, and increasing power without strengthening the transmission will cause the entire trimmer mechanism to fail quickly.
Step-by-step instructions for engine installation
The process of replacing the engine requires care and a basic set of tools. Before starting work, make sure the gas tank is empty and disconnect the candle wire to prevent accidental start-up. Safety when working with gasoline equipment is the number one priority.
First, you have to disassemble the old engine, and to do this, unscrew the mount bolts that connect the motor to the rod pipe, and be careful with the thrust of the gas: it can be secured by a clamping or a screw, and it must be carefully disconnected, remembering or photographing the connection order.
☑️ Preparation for installation
The new unit is installed in reverse sequence, and it is important to correctly combine the slits of the engine shaft and the clutch shaft (or intermediate shaft). If the slits do not match, slightly rotate the shaft of the engine with your hand until the characteristic click.
- Install the engine on the landing place and make fasteners.
- Connect the thrust of the accelerator, making sure that the carburetor valve walks freely.
- Twisting the mount bolts using the thread locker for reliability.
- Check the tightening of all connections before the first start.
After assembly, you need to start and run in the first place. Don't put the new engine on full load at once. Let it run at idle speeds for a few minutes to warm up and distribute the lubrication.
Set up the carburetor after replacement
Replacing the engine almost always requires reconfiguration of the carburetor, factory settings may not correspond to the operating conditions or specifications of a particular instance of the engine, correct adjustment ensures stable idling and no dips when sharply pressed on the gas.
On the carburetor there are usually three adjusting screws: L (low revs), H (high turnover) and T or LA (idle) The setup should start with the idling screw, achieving stable operation without movement of the trimmer head.
Use the tachometer to fine-tune your maximum speed if possible, and exceeding the allowable speed can cause the piston group to collapse.
Screws. L and H They control the composition of the fuel-air mixture. The screw twisting impoverishes the mixture, the twisting enriches the mixture. The optimal adjustment is achieved by sampling, carefully turning the screws 1/4 revolution and checking the engine response.
⚠️ Attention: A poor mixture (lots of air, not enough fuel) is dangerous with overheating and piston blows. If the engine squeals at high speeds or stalls when you set speed, the mixture is too poor.
The first break-in and the first start of the new engine
The first hours of operation of the new engine are crucial for its future life: the process of running in allows the parts of the cylinder-piston group to get used to each other, ignoring the rules of running in can reduce the life of the engine by half.
During the first 3-5 tanks of fuel, it is not recommended to work at full speeds all the time. Take breaks, let the engine cool down. Work in a gentle mode, mowing soft grass, avoiding thick stems and dryness.
- 🛢️ Use a high-quality mixture of gasoline and synthetic oil in a ratio of 1:40 or 1:50 (see the instructions).
- ⏱️ Duration of the first break-in: approximately 2-3 hours of total working time.
- 🌡️ Watch the temperature of the engine body: it should not heat up to blue.
High-quality running on the right mixture of oil and gasoline is the key to a long life of your new engine without bulldozers and overheating.
After the first tanks are developed, it is recommended to check the tightening of the fasteners, as they may weaken from vibration, and check the condition of the air filter - if it clogs with dust at the first start, it is better to clean or replace it.
Frequently Asked Questions (FAQ)
Can I use an engine from one brand on the trimmer of another?
Yes, it's possible if the landing dimensions, the shaft diameter and the direction of rotation match, but you may need to adjust the mounting system or the carburetor.
Which gasoline is best used for a new engine?
It is recommended to use AI-92 or AI-95 gasoline from proven gas stations, and it is important that the fuel is fresh, as old gasoline loses its properties and forms a resinous plaque.
Why does the new engine smoke on the first run?
When you first start, you can burn out the conservation lubricant that got into the cylinder when you assemble it, and if the smoke stops after 5 to 10 minutes, that's OK, and the smoke is always there, and it's a problem.
Do I need to change the spark plug when installing a new engine?
New engines usually come with a candle, but the quality can be low, and it is recommended to install a quality candle immediately (such as NGK or Champion) for confident start-up.
How to store a trimmer with a new engine in winter?
You need to completely develop the fuel from the carburetor or drain it, and you should also lubricate the cylinder by pouring some oil into the candle hole and turning the shaft several times.