Look in the corner, you’ll notice a puddle of sticky orange goop beneath your feet. It look a bit like syrup mixed with motor oil. That’s bar oil, and it smells distinctively synthetic (and looks like motor oil).
It is not only gross but it is also a red flag that your Stihl chainsaw might be running low on lubricant and wasting fuel and resources while doing so. When the leak happens on your Stihl chainsaw most people immediately think it’s either the reservoir or the pump. And sometimes, it is.
Often times it’s not. That’s good news because it’s not typically something that has to be taken to dealer. Most of the time it’s just cleaning up neglect, swapping out a worn part or making an adjustment or two in the settings.
So what’s the problem? Most of the time, it’s the pump gear adjustment. On Stihl saws, they is designed with a screw.
Fixing Stihl Chainsaw Bar Oil Leaks
Adjusting the Oil Pump Gear
This screw adjust how many teeth on the pump gear engage with the drive shaft. Turn that up too far and now the pump is giving you more oil then your bar can handle. Where does that excess go?
Out, of course. Even with the chain stopped, you’ll notice a consistent drip. Most folks think more oil = better lubrication.
Not true. More oil = slippery floors. To adjust the oiling system, first find the adjustment screw located just in front of the chain brake under the hand guard.
Sometimes it take a small screwdriver to rotate it. Rotate it 1/4 turn down then take your saw and cut on a piece of scrap wood. Look at the oil trail on the wood.
Is it dripping and heavy? Turn it down a bit more. Is there no oil showing?
Then you’ve gone too far. You want a nice even smear of oil but not dripping. It’s a balance thing.
You don’t want it running off the end, or it won’t cool the bar. But you don’t want to little either.
Inspecting the Drive Chain
If your leak continues even though you have adjusted the pump correctly, check the drive chain on the pump assembly.
The drive chain is a tiny little chain that connect your engine to the oil pump. It is exposed to elements. It also faces heat and sawdust over time.
And guess what? It gets stretched out. A stretched out chain will slip.
It won’t fully engage the pump gear. This can cause the pump to start and stop, leading to irregular pumping or even a surge of flow that overwhelms the bar. Here’s the clutch cover removed.
The sprocket and chain should fits snugly with no obvious space, and there shouldn’t be any wear in the links. A new drive chain can be replaced easy as part of routine service, and it’s very reasonably priced. This keeps your machine tuned just the way it was designed to run, and avoids costly problems later.
Skipping it means an out-of-tune machine that doesn’t get adequately oiled and could stress the engine.
Checking Bar Fittings and Seals
Sometimes the leak is not coming from the pump at all. At the top end of the bar there are fittings that join the bar to the oil delivery system on your saw.
The threads is small. If they become cross-threaded, stripped, or filled with hardened debris, the oil will leak out right at the connection. Clean up those fittings with a wire brush and make sure they fit.
The tight one hold, the loose one drips like crazy. So do seals. Inside the clutch bell is what’s called a shaft seal.
It can get old and crack and dry out over time. You may notice oil leaking at the side of your saw where the clutch is located or near the muffler. If you see oil weeping from the side, it could mean the seal is blown and you’ll have to pull it apart to work on the clutch housing.
A more complex fix than messing with a screw. Not something I’d try if I wasn’t comfortabley with. Take it in to the shop.
For most leaks though, it’s pretty simple. Solving a leaky chainsaw is really all about attention to detail and patience. Adjust the pump first.
Examine the drive chain. Look at the bar fittings. These things will not only stop the mess but also get the proper lubrication to your bar.
Your saw runs well and your boots stay dry.