help with bar oil pump

[Muddy42]

I have been trying to find the issue with my Stihl MS460 that suddenly stopped oiling the bar at all.  So far I have tried cleaning out the bar groove and oiler hole and I've flushed out the oil tank with petrol, dried then refilled with bar oil.  The filter in the oil tank looked fine.  I've just removed the clutch to look at the oil pump area.  The worm gear looks fine and seems to be engaging with the clutch fine.  I've removed the oil pump, which also didn't have anything obviously wrong with it, aside maybe from the fact that the adjustment screw that increases the oil output just seems to turn 360 degrees rather than coming to a stop at max output? Below the oil pump I am unsure which holes go where - the red hole has oil in it but the green hole is dry.

 

Does this mean that the whole oil pump needs replacing? Thanks

 

[Bob_z_l]

If it was me and I'd got as far as taking the pump out I'd probably replace it.

 

One less thing to thing about in the future. One more likely suspect crossed off the list.

 

[Muddy42]

21 minutes ago, Bob_z_l said:

If it was me and I'd got as far as taking the pump out I'd probably replace it.

 

One less thing to thing about in the future. One more likely suspect crossed off the list.

 

Yes I probably will replace it anyway. The fact the adjustment turns and turns doesnt seem right.

[adw]

 Not a Stihl lover but the ones I have seen have the crank so badly worn the sprocket  drum recess comes away from the pump actuating arm so does not turn it, so no oil.

[Muddy42]

1 hour ago, adw said:

 Not a Stihl lover but the ones I have seen have the crank so badly worn the sprocket  drum recess comes away from the pump actuating arm so does not turn it, so no oil.

Yes I have seen that issue, I dont think thats a problem here, the metal arm is attached firmly the plastic threaded part.

[handcutter]

Check the pickup pipe, I’ve had a few with restricted flow from tiny bits in them 

[Con]

Part of the adjusting screw damaged/ snapped (or thread) causing blockage? 

Edited January 28 by Con

[spudulike]

The MS460 is like the MS660 and is pretty much bullet proof. I have never seen pinion issues with this saw so it is most likely that the oil pump is plugged with fine saw dust. The oil will flow from your RED bit so any blockage will be on this part of the oil pump. If you get an aerosol with one of those small pipe appendages like WD40 has, stick it in the hole that connects with your GREEN hole and blast it down there. If nothing comes out of the other hole, it is most likely plugged with shyte and it needs cleaning out. You can either strip it or try blasting it with a compressor etc.

Other than that, make sure you haven't worn the end off your oiler arm see below pic....this is relatively common on saws that are 10-20 years old and can be difficult to see. Check that the end of the arm is locating in the slot in the sprocket. If it isn't. the end has completely worn off. This was very common on low hours MS261s a few years ago but I have seen issues on well used 460s - not a design issue but just an issue found on saws that have lasted a bit too well.

[Muddy42]

24 minutes ago, spudulike said:

The MS460 is like the MS660 and is pretty much bullet proof. I have never seen pinion issues with this saw so it is most likely that the oil pump is plugged with fine saw dust. The oil will flow from your RED bit so any blockage will be on this part of the oil pump. If you get an aerosol with one of those small pipe appendages like WD40 has, stick it in the hole that connects with your GREEN hole and blast it down there. If nothing comes out of the other hole, it is most likely plugged with shyte and it needs cleaning out. You can either strip it or try blasting it with a compressor etc.

Other than that, make sure you haven't worn the end off your oiler arm see below pic....this is relatively common on saws that are 10-20 years old and can be difficult to see. Check that the end of the arm is locating in the slot in the sprocket. If it isn't. the end has completely worn off. This was very common on low hours MS261s a few years ago but I have seen issues on well used 460s - not a design issue but just an issue found on saws that have lasted a bit too well.

Thanks. I’ll investigate these tips.

[Muddy42]

This is really mysterious.  I can blast air and WD40 through everything - from the oil pump to the oil tank, through the oil pump and from the oil pump to the bar hole.  Initially the pump provided a lot of resistance, but this is improving.  I can tell that the end of the worm arm is worn but it still works - I can see its locked into the clutch drum as I move this around.  Also it turns the cogs of the oil pump if I hold them together. But if I turn the sprocket with a drill and elastic band - no bar oil emerges.

 

My only guess is I need to keep freeing up the oil pump - maybe syringe some hot soapy water or white spirit through.