Problem with my MS 661

[spudulike]

Well, the oil is supposed to come out of the oiling channel and would normally go through the oiler hole in the bar and lubricate the chain.

 

If it is leaking out, the bar can't be sealing the oiling channel so the bar is the wrong one, the oiler hole in it is blocked or the bar mount is damaged. With the bar fitted, is it clamped up tightly against the bar mount? 

 

The oiler is adjustable but on the 661, it is a two position affair - I found this out on a customers machine where he wanted more oil and there wasn't much I could do to effect this.

 

The oiler does have a sealing ring (part 1122 649 5000) underneath the pump that seals the pump outlet to the oil channel inlet. If this has somehow been left off, oil would piss out from the bottom of the machine. 

 

If this is present, you could use some light pressure with a soft rubber tube stuck down the oiler channel feed hole and see if bubbly water bubbles from anywhere on the casting.

[spudulike]

BTW - you do know your bar plate is missing....don't you.

This thing....It won't help if it is!!

Inner Side Plate 0.9 mm for Stihl MS440, MS460 Chainsaws - 1128 664 1001 | L&S Engineers

WWW.LSENGINEERS.CO.UK

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Inner Side Plate 0.9 mm for Stihl MS440, MS460 Chainsaws Genuine Stihl Part OEM Part No. 1128 664 1001 Suitable for...

 

Edited May 1, 2022 by spudulike

[keptenjim]

3 minutes ago, spudulike said:

BTW - you do know your bar plate is missing....don't you.

This thing....

Inner Side Plate 0.9 mm for Stihl MS440, MS460 Chainsaws - 1128 664 1001 | L&S Engineers

WWW.LSENGINEERS.CO.UK

---

Inner Side Plate 0.9 mm for Stihl MS440, MS460 Chainsaws Genuine Stihl Part OEM Part No. 1128 664 1001 Suitable for...

 

Yes I took the side plate off to enable you to check for damage in the casing underneath. Also, I only run the chainsaw with the chain tensioned and the bar firmly tightened up to the bar mount

[spudulike]

If the bar is fully clamped against the bar mount and the bar is correct for the machine, oil can't escape between the bar and the mount.

I have seen old pumps leak from where the pump gear shaft enters the pump but that is from wear on the shaft so is unlikely on a near new machine. 

I guess you could seal the oil channel with a piece of paper/card clamped between the bar and mount to see if you still get oil pissing out. Run the chain semi loose and don't cut wood with it though, just rev it a bit. If it still pisses out, it isn't the mount that is an issue.

This one is a bit weird!

If this doesn't help, perhaps take the pump off and check for the seals on pump inlet and outlet.

 

[keptenjim]

13 hours ago, spudulike said:

If the bar is fully clamped against the bar mount and the bar is correct for the machine, oil can't escape between the bar and the mount.

I have seen old pumps leak from where the pump gear shaft enters the pump but that is from wear on the shaft so is unlikely on a near new machine. 

I guess you could seal the oil channel with a piece of paper/card clamped between the bar and mount to see if you still get oil pissing out. Run the chain semi loose and don't cut wood with it though, just rev it a bit. If it still pisses out, it isn't the mount that is an issue.

This one is a bit weird!

If this doesn't help, perhaps take the pump off and check for the seals on pump inlet and outlet.

 

Thanks, I'll try this and let you know - John 

[keptenjim]

On 02/05/2022 at 19:39, spudulike said:

If the bar is fully clamped against the bar mount and the bar is correct for the machine, oil can't escape between the bar and the mount.

I have seen old pumps leak from where the pump gear shaft enters the pump but that is from wear on the shaft so is unlikely on a near new machine. 

I guess you could seal the oil channel with a piece of paper/card clamped between the bar and mount to see if you still get oil pissing out. Run the chain semi loose and don't cut wood with it though, just rev it a bit. If it still pisses out, it isn't the mount that is an issue.

This one is a bit weird!

If this doesn't help, perhaps take the pump off and check for the seals on pump inlet and outlet.

 

Finally managed to get this done. I tried what you suggested and blanked out the oil channel using a piece of cardboard and then mounted the bar and made it nice and tight. I ran it in the manner you suggested and sure enough, oil was pissing out. So, I stripped it down and found that although the cardboard was still in place, there was evidence of oil having flowed down from the oil channel. Perhaps after the run, there was a residual pressure in the oil channel which equalised when I removed the bar and caused a bit of oil to squirt out around the cardboard? However, as you can see, there was also quite a lot of oil in the pump compartment. I’m thinking, maybe its time to fit a new oil pump and be done with it?

[spudulike]

Take the pump off and check there is a rubber round seal between the pump output and the oil channel input. My money is on it missing, damaged or split. 

The pump looks too new to be faulty unless it has been damaged somehow. I don't suppose you have had the crank seal changed recently? It needs to be flush otherwise it doesn't allow the pump to sit flat but generally stops the pinion spinning freely.

Still a strange one for a fresh looking saw!

[keptenjim]

On 08/05/2022 at 22:34, spudulike said:

Take the pump off and check there is a rubber round seal between the pump output and the oil channel input. My money is on it missing, damaged or split. 

The pump looks too new to be faulty unless it has been damaged somehow. I don't suppose you have had the crank seal changed recently? It needs to be flush otherwise it doesn't allow the pump to sit flat but generally stops the pinion spinning freely.

Still a strange one for a fresh looking saw!

The rubber seal looks ok to me, or should I take it out of it's housing and inspect it? The crank seal hasn't been changed lately 

 

 

 

[spudulike]

You could pop it out and refit the other way round with a smear of liquid gasket on it. If the saw only leaks when it is running, it must be leaking from after the pump to the bar. Not sure I can come up with any other ideas as to what is causing it. 

I think I would be using a Mityvac on the oil channel feed hole with the pictured hole blocked to see if it holds pressure. It may be worth replacing that pictured seal...not the crank seal!!!

[bmp01]

Can you come up with a way to drive the oil pump without the clutch in place or engine running?  I'm thinking battery drill and an adapter or rubber drive drum (like the rubber drum you have in a demel kit for the sanding drum). Blank off the outlet to the bar, as youve done already. Spin the pump and look for leak. ...