Chainsaw Over-Oiling, what to do? Tips from a Professional


Lubrication is an essential chainsaw maintenance step, which ensures longevity and better performance of its components. Maintaining an adequate amount of lubricant is critical to grease the guide bar and its chain. Sometimes, you may notice that the oil which runs through the bar and chain seems more than usual. In such cases, this blog post can help you determine if your chainsaw is over-oiling and how to fix it.

Chainsaw over-oiling, what to do:

  • If your chainsaw is over-oiling, check if the oil tank is ventilated or not. Open it for some time to equalize the air pressures.
  • Check if the stud at the bottom of the oil tank is displaced or not.
  • Examine the oil tank and ensure that it isn’t overfilled.
  • Inspect the oil lines under the chainsaw for any leak.
  • Adjust the bar oil screw by turning it out to reduce the oil flow to the chain.

In this blog post, I will look into more detail what you can do about chainsaw over oiling. And explain the reasons why your chainsaw is leaking oil, even when not in use.

How does a Chainsaw Oiler Work?

In modern chainsaws (gas and electric), the oiling mechanism is performed by an oil reservoir with an oil pump. As the throttle is pushed, the oil pump releases the lubricant from the reservoir on the guide bar while the chain is rotating. It is then distributed on the bar evenly by the moving chain.

The purpose of a bar and chain oiler is to provide enough lubrication to the chain, which reduces friction and prevents it from overheating. In older chainsaw versions, an oiling mechanism was non-existent, and the user had to manually pour the oil in the middle of the cutting operation. As chainsaws evolved, an onboard oiling plunger was introduced. The user had to press it to lubricate the chain fully manually.

Then came the modern chainsaws with automatic oiling mechanisms, which are in use today. These ‘oilers’ consist of an oil pump which is driven by a worm drive from the engine’s throttle. The pump sends oil into the bar-chain groove without the user having to interfere.

The oiling system is usually of two types. It can be fixed flow oiling or adjustable flow oiling. In fixed flow, the pump sends oil at a constant rate regardless of the temperature or device RPMs. In an adjustable flow oiling, the amount of oil that goes into the bar and chain can be controlled by an adjustable screw. The screw has plus and minus signs to increase or decrease the oil flow, respectively. Hence, on a hot day, the user might want to adjust the screw to draw more oil for the chain.

Checking the Oil Level:

Checking the oil level in the chain oil reservoir before each use can establish whether or not there is enough oil available for use. If the oil level is low, add some before continuing. The appropriate type of oil for your chainsaw is specified in the owner’s manual. Start the chainsaw’s engine and run it for a few minutes. Allow the chain to spin around the guide bar while pointing it at a piece of wood. Examine the wood to confirm that the chain throws minor amounts of oil while in operation and before cutting.

If you notice an unusually high quantity of oil dripping from the guide bar or the reservoir, then there can be various reasons behind it. Let’s investigate the causes of the over-oiling of a chainsaw.

Why does my Chainsaw Leak so much Oil?

A chainsaw could leak oil if the oil tank isn’t properly ventilated or if it has a misplaced stud that secures its port. An overfilled tank might be another cause behind the issue. In most cases, a large amount of oil beside a chainsaw isn’t due to an actual leak.

Expert’s perspective: Most new chainsaw users get concerned when they see oil around their device in a significant quantity. Based on my experience dealing with chainsaws, I can assure you that seeing this oil around is a fairly common occurrence. It is quite usual for a chainsaw to leave oil, especially after cutting.

Most new chainsaws fling oil off the chain in the form of a fine mist on the guide bar. When these droplets accumulate, they run down the guide bar, and the user might suspect if there’s an oil leak. Also, the clutch, the bar’s groove, and the sprocket release some oil droplets which accumulate during cutting. Please note that it is not a leak.

To prevent this oil from causing a mess, I recommend placing dry cardboard under your chainsaw whenever you intend to store it. Oil leaks are characterized by a constant rundown of oil across your device. Furthermore, you constantly need to replenish the oil in your reservoir in case of a leak. When you identify that it’s a leak, you should follow the necessary troubleshooting steps mentioned further in this article.

Identifying an Oil Leak:

To determine whether the oil puddles are due to a leak or just a normal throw-off from the chainsaw, store your chainsaw in a dry place for a few hours. Before storing it, make sure it’s clean from any oil residues and note down the oil level in the tank. After some time, if you see a decrease in the oil level in the tank along with puddles of oil around the device, then it’s a sure shot sign of a leak.

To save time, an alternate approach can be performed.  Place a paper in front of your chainsaw and run it for some time by placing the guide bar directly above the paper. Small oil droplets on the paper are just a sign of normal oil throw-off. However, if the paper gets soaked in oil, then it’s a concern.

Usually, one tank of bar oil is used per tank of fuel. But in case of a leak, the oil consumption increases drastically. You might need to add oil more than once or per unit of fuel.

Why does my Chainsaw Leak Bar Oil when not in Use?

A chainsaw that leaks oil is certainly not a good sign. Not only will this result in a mess, but it could also affect the chainsaw’s performance. You might need to add oil time and again in your chainsaw. Let’s look at some common reasons why a chainsaw could leak bar oil when not in use.

1. Poorly ventilated oil tank

This is the most significant factor which could be causing oil leaking in your chainsaw. Chainsaw oil tanks need to be ventilated to prevent vacuum formation. Furthermore, the air pressure needs to be equalized between the tank and the atmosphere. Most tanks come with a one-way valve that allows air to flow into the tank to maintain the air pressure. At times, when temperature changes are drastic, the air pressure changes inside the tank.

For instance, if at night, the air pressure in the tank falls due to a temperature drop. This causes air to flow into the tank and equalize the pressure. During the day, as the temperature rises, the air pressure also rises. Since the valve is one way, air cannot flow out of the tank, due to which the only way to equalize the pressure would be to drip off some oil from the ports. This condition is more significant in places that experience sudden temperature changes.

– Solution:

Fixing this issue is fairly simple. Just unscrew the oil reservoir’s cap by some amount to adjust the air pressure inside the tank. With the pressure equalized now, no oil would be forced to leak out of the ports.

After making this adjustment, tighten the cap of your oil tank. I recommend performing this simple step whenever you’ve started your chainsaw on a hot day after letting it sit for the night.

2. Displaced stud:

In most chainsaws, a stud lies at the bottom of the oil tank and is visible from the muffler’s side. If the stud is missing from its place, it will most likely result in leakage. It is pretty small in size (about 0.1 inches in diameter) and is highly likely to be get displaced. To check for this, you need to peek from the muffler’s side using a flashlight and see if you see the stud or if a hole is visible.

– Solution:

You will need the stud’s part number to purchase it from the local dealer. Check the owner’s manual to see if you can locate the part number. If not, it’s pretty easy to get a similar-sized stud from any hardware store. Just make sure that you buy the part with the same diameter as the hole’s, and its length isn’t too long.

3. Overfilled oil:

After talking with many chainsaw users, this is the most frequently reported cause of over-oiling. When the oil tank is overfilled, there is always a possibility of oil seeping into the sprocket and the chain, and it may seem like there’s a leakage. This is quite predominant in conditions where the temperature variations are significant. Due to a sudden temperature rise, the oil which is already overfilled may expand and seep into parts of the sprocket and guide bar assembly.

This overfilling phenomenon also holds for the engine oil and fuel. If the oil-fuel mixture (also known as premix) is overfilled in the tank, the chances of seepage are pretty high.

– Solution:

Just make sure that you haven’t overfilled either the bar oil reservoir or the fuel tank with an oil mix. Even if it were overfilled, the excess oil would have been released out by the chainsaw, and it shouldn’t leak any more oil.

4. Leaking oil line:

The oil line carries the bar oil from the tank to the oil pump. The tube may be punctured due to which some amount of oil leaks out of it. To check if the line is faulty, tilt your chainsaw over and remove the lower cover. If there’s a large amount of oil buildup in that region, it is most probably a ruptured oil line.

– Solution:

Check that the oil reservoir has been emptied before reinstalling the oil line. Unscrew the engine mounting nuts and fasteners (if applicable) to gain access to the line. To remove it from the holes, use a flat head screwdriver. Install a new oil line in its place and reconnect everything that was removed.

How do you adjust the oil on a chainsaw bar?

The bar oil is adjusted through an adjustment screw. By turning the screw out (counterclockwise), you can increase the amount of oil that goes to the bar. Similarly, turning the screw in (clockwise) reduces the oil flow to the bar.

The oil adjustment control is situated under the chainsaw. The adjustment screw controls the oil flow to the oil pump. Most chainsaws have a marking on the screw (by a plus and minus sign) that tells us about the direction the screw must be turned.

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