HELP! Stihl MS 260 Pro oiling problems, burning up bar and chains

[jmfcst]

Hello forum, first time poster...original owner of absolute bullet proof MS260 Pro...I have only done very basic maintenance over the years: air filter, fuel filter and lines, exterior cleaning of saw, new chains, etc....

It is burning up new bar and chains just by revving, in fact it is melting tips chain linkage (side which rides in groove of bar) and blue-ing bar...verified correct bar and chain for 260 pro model...chain is not overtightened...took bar off, oil is coming out of oil port when revving engine...but when bar (old or new) and chain is installed, saw is barely (I mean barely) spraying oil, *BUT* oil is dripping to the ground from sprocket area *AND* oil is being used at same rate as fuel....bars (both old and new) are 100% perfectly clean including oil ports....so oil is making out of saw port and into bar port but is not being sucked onto the chain.

Is this an oil pump issue?

 

[cus_deluxe]

check that bar plates are in place. im not super familiar with the 260 but other saws i know of the bar plate plays a role in directing oil into the bar.

 

[jacob j.]

Is your sprocket severely worn? Check the oil input holes on your bar and make sure they aren't plugged. As Custer posted above - make sure your bar plates are in place and are clean. Make sure your chain pitch matches the sprocket and make sure the gauge of the chain matches the bar - time to take a deep dive in learning more about your machine. Also check the clutch drum for excessive wear.

 

[Junk Meister]

Is your sprocket severely worn? Check the oil input holes on your bar and make sure they aren't plugged. As Custer posted above - make sure your bar plates are in place and are clean. Make sure your chain pitch matches the sprocket and make sure the gauge of the chain matches the bar - time to take a deep dive in learning more about your machine. Also check the clutch drum for excessive wear.

I have seen warped/tweaked side plates allow bar oil to take the course of least resistance and not to the bar itself. Does the 026/260 have the same oil delivery as the 034? If that tube is melted or has a hole in it, the oil will again take the route of least resistance.

 

[Wood Doctor]

On occasion when this happens I remove the bar and chain, start the saw engine, and check to see if any bar oil is flowing it out the port when I goose the engine. You could have just a clogged oil port that is blocking the flow. That's worth checking.

 

[Outback]

You said its coming out under the drum. Take off the drum, clean it. Put the drum back on and bar and chain. Run it for a minute. Take the drum off and look/check for leaks. Do not run it with the drum off to look for leaks. You said its using oil at the correct rate so the pump is likely good. Its pumping fine without back pressure when the bar is off. Its not with the bar on, so I would guess the line from the pump to the bar pad is damaged. Part #21.

 

[Junk Meister]

You said its coming out under the drum. Take off the drum, clean it. Put the drum back on and bar and chain. Run it for a minute. Take the drum off and look/check for leaks. Do not run it with the drum off to look for leaks. You said its using oil at the correct rate so the pump is likely good. Its pumping fine without back pressure when the bar is off. Its not with the bar on, so I would guess the line from the pump to the bar pad is damaged. Part #21.
View attachment 454625

Inspect hose part #21 and the rubber ?boot? between the hose #21 and where it meets the bar.

 

[Mad Professor]

Inspect hose part #21 and the rubber ?boot? between the hose #21 and where it meets the bar.

They have a brass nipple insert, that fits the case on the bar end and spring insert to keep the hose from kinking. The hose is stiff as a sailor on shore leave. Stihl suggests modifying a cheap set of slip joint pliers to install the hose on the pump. I gently heat the hose to soften it up.

The OEM Stihl hose has enough to do 2 saws

Here is a 036

 

[Junk Meister]

I did a 034Super and at the time noted the hose was long enough to do 2 saws. I vaguely remember this same hose fit the 088 saws as well.