Design and operation of the chainsaw oil pump

A groove in the shank ensures that the oil from the saw’s oil reservoir is captured and fed to the hose that feeds it to the guide bar.

Plunger on brand name saws is made of one solid metal rod. But in cheaper types, the pinion is usually not only forged, but also mounted on the plunger stem, which naturally affects the service life of the part.

The groove on the end has several types:

  • There is a ½ to 1/3 of the plug diameter longitudinal groove in the body to capture the oil;
  • Radial groove on the face permits plunger misalignment relative to the axis.

It is important when replacing the oil pump to pick up all the parts exactly this series of chainsaws for maximum alignment of all the protrusions and grooves with the body and the eccentric regulator.

Chainsaw chain lubrication system

In order to supply oil for chainsaw chain lubrication, a special pump is used in the tool, which doses the lubricant to the saw bar according to the number of engine revolutions.

The system uses chainsaw chain oil, which has increased adhesive properties, it is necessary for the oil to distribute evenly over the entire perimeter of the bar and retain it even at high chain rotation speeds. Let’s take a closer look at the oil supply system implemented in modern chainsaws.

Causes of reduced productivity and efficiency of the system

There are several reasons why chainsaw chain oil is not supplied in the right quantity. Among the most typical failures, we can name:

  • clogging of the filter located in the oil tank;
  • mechanical failure of one of the elements of the worm pump drive;
  • in the winter, the high-pressure pump’s performance is slowed by too thick an oil in the system.

In the latter case, the drives and all parts of the pump work under increased loads, initiating serious mechanical damage.

Troubleshooting the chain

Always keep the chain lubricated while the chain saw is in operation. This is the part that has to work under the most severe conditions. The chain is subjected to constant overheating and is blocked by dust and abrasive particles. All this has a negative effect on its service life. This can be corrected with special lubricant. This is fed to the chain from a reservoir, so it works flawlessly.

If there is no lubrication during operation, there is a high probability of overheating. When oil is not available, the chain can become stretched. And it can still get stuck or come off by itself, which can lead to serious injury.

Channels through which the fuel supply can be clogged with small particles, so it is advisable to clean them periodically. It is important to keep an eye on the oil level in the tank. Debris in the channel is a frequent cause of the chain brake not working. This can have a negative effect on the function.

chainsaw, chain

Regular channel cleaning and general care will keep your chain saw in good working order for a long time.

But what if all the recommendations are followed, but the oil still leaks. Check that chainsaw is working properly. It is very likely that it has not been assembled properly. If the fault is not detected, it is advisable to take it to a workshop. In some cases it is necessary to replace the pump, but this should be done if the saw is new. Old tools are leaking because the tank is worn out.

The current state of the chainsaw can only be assessed by an expert. In the absence of knowledge or lack of confidence in their own abilities, it is advisable to entrust the repair of the tool to a professional.

Every chainsaw, regardless of model, make or class has basically the same design. It consists of several important components, including the lubrication system. Without the latter, the operation of the power unit is impossible. Through the functioning of the forced lubrication system, the chain of the tool reduces the risk of severe wear, which is guaranteed in conditions of constant friction of the cutting element against the guide bar, the inevitable heat. Chain lubrication softens friction, making the chainsaw operator less likely to need to repair or completely replace the element.

Price range and repair warranty in workshops

If you have a chainsaw, it is always worth having spare parts with you to be able to make repairs on the spot if necessary. Amateurs should never attempt to repair a chainsaw themselves. Improper repair can lead to a more serious failure. Many service centers are available for repair. try there. Repairs can be made within a certain period of time. In good firms the minor repairs are carried out in just two or three days, but if the breakdown is serious, then you have to wait about a week. Always pay attention to the warranty when choosing such a service. It should be on the parts themselves, as well as on the work!

(or thereabouts).

Don’t be instantly intimidated. Look through the reviews and maybe you have come across a really good repair shop, where you will get a quality repair at quite attractive and nice prices. Have a good time with your chainsaw and take care of yourself when working with it. Follow the safety instructions and you will be fine.

The chainsaw chain generates a great deal of heat in the bar groove as it moves. If there is no oil flow to the chainsaw chain, it is necessary to stop work and take all measures to fix the faulty lubrication system. The combination of heavy loads and overheating is accompanied by accelerated wear and early failure of the headset.

  • All chainsaws and their electric counterparts without exception are equipped with the same functional principle of lubrication of guide bar, chain and chain drive components.
  • This unit includes, as standard, a reservoir from which chain oil is pumped to a fixed or adjustable capacity pump inlet.
  • The dosed amount of working fluid then enters the bar groove, where the saw chain shanks distribute it evenly over the whole chainring and the working surface of the drive sprocket rim.

The chainset has a driven sprocket and is 400 mm or more in length. The periodic lubrication of the bearing is done individually after 6-8 hours of operation.

Lubrication system malfunctions and how to correct them

The main faults of the oil supply system on a chainsaw can be divided into two main types, these are general faults inherent to all chainsaws and individual faults, which may differ depending on the type of pump and worm gear installed on a particular model. Let’s start to troubleshoot in order.

3 Easy Ways To Check If Your Chainsaw Is Oiling The Bar & Chain. Video

It is forbidden to use the chain saw if the chain is not lubricated. This is detrimental to the bar, drive sprocket and chain and can be costly to repair.

Signs of malfunction of the lubrication system, check its efficiency

  • Chainsaw chain is dry and has a pale shade without shine.
  • The chain is stretching relatively quickly.
  • The bar is very hot and can even partially melt the paint.
  • The oil in the tank is almost never drained.
  • The cutting performance of the sharp chain is reduced

All of these signs are an indication that the lubrication process is not working properly. To check oil flow in the lubrication system, remove chainsaw side bar and start the chain saw. Next, you need to increase the RPM a little, watching for the end of the oil line. If oil is coming in, there is most likely not enough oil for proper lubrication and the filter should be cleaned or replaced and if possible the flow should be adjusted. In the case when it does not come, the problem is more serious and requires further diagnosis.

There is a way to check the oil flow without removing the tire. it is necessary to direct the end of the tire to the side of e.g. a freshly cut billets from the cutting side and increase revolutions as much as possible, you should try to keep the tire end not more than 10 cm from the billets. If oil stains begin to appear on its surface. then the oil is fed.


Once it has been determined that there is no oil supply, further diagnosis is only possible if the oil system is completely removed. Of course in some situations changing the filter helps, but it is very rare.

Access to the oil pump for some models of saws is possible only after a complete disassembly, respectively, having no skills in the repair of power tools, the repair is better to trust professionals.

Most common faults

  • Broken oil hose. It can sometimes be detected by visual inspection as well. The problem can be solved by replacing the defective part.
  • Lack of thread on the oil pump shaft, replacing it will help.

STIHL MS 180 Individual fault in the lubrication system

Since the STIHL MS 180 is one of the most popular chain saw models, we would like to dwell on a particular characteristic malfunction and explain how it can be fixed without having to change parts.

STIHL MS 180 chain saws often have a leak in the oil pipe where the oil pipe from the oil tank is inserted into the chain saw. The defect can be identified by characteristic grease leakage on the bottom of the tool.

To eliminate the problem, first remove the chain saw handle, then remove the hose from its seat hole and clean and degrease. After all these manipulations, apply sealant to the seat of the hose and install it in the chainsaw body.

To learn more about how to troubleshoot and fully diagnose the STIHL chain saw lubrication system, watch this video, which shows step by step how to disassemble and repair the lubrication system.

Failures of oil pump

Regardless of the manufacturer, faults in the lubrication system occur in any chainsaw model.

chainsaw oil pump assembly

The lubrication system isn’t always what it looks like, so before you start repairing it’s important to find out exactly what’s causing the leakage or the leakage on the bar. If you exclude the possibility of mechanical damage, you can highlight the following breakdowns of the lubrication system:

  • The line to the outlet channel of the chain saw oil pump is not sealed;
  • Parts do not fit tightly in the plunger system;
  • Misalignment of the discharge chamber and plunger dimensions;
  • Oil line is leaking from oil pump inlet connection.

It must be remembered that if the plunger system is not sealed and the lubrication tank is located above it, there will be a rapid leakage of oil (2-3 days).

It is quite easy to repair an oil leak from a chainsaw if it has not been used for a long time. You will need some screwdrivers and wrenches.

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