Ms 390 stopped oiling

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Woody Longbranch

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The other day I was cutting up some 20 " in Maple into firewood and ms390 started oiling the bar heavily, lots of oil coming out on the bar and chain to the point where it was smoking, finish the job, a couple days later I went to use the saw and no oil was coming out I haven't pulled it apart yet what could I expect? Has anybody ever had this problem. Is the oiler plastic Gear with a a wire coming out of it that goes into the clutch drum?
I'm familiar with the setups on the 210s and he 250s but I haven't taken apart a 390 before? Any help or insight is appreciated thank you.
 
The other day I was cutting up some 20 " in Maple into firewood and ms390 started oiling the bar heavily, lots of oil coming out on the bar and chain to the point where it was smoking, finish the job, a couple days later I went to use the saw and no oil was coming out I haven't pulled it apart yet what could I expect? Has anybody ever had this problem. Is the oiler plastic Gear with a a wire coming out of it that goes into the clutch drum?
I'm familiar with the setups on the 210s and he 250s but I haven't taken apart a 390 before? Any help or insight is appreciated thank you.
Fill oil and run with bar and clutch cover off too see if oiling out the hole and no where else. Good idea to get repair manual partsb list from Beg for Manuals thread. I had a MS 310 that poured oil out front by bucking spike. A tiny grub screw had come out. Good luck and let us know.

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Just take off the sprocket and see if you can see the tang/tip of the worm drive tip behind the clutch, it is turned by the notch in the back of the sprocket drum. It's tip may have worn/broken off.
 
The "plastic thing with a wire" you see is the oil pump worm gear. If the wire is actually aligned with the notch in the clutch drum, the clutch will need to come off.
From my experience with 1127-series saws and what happened (lot of oil first, then no oil at all) it's likely your oil pump has burst: those oil pumps are mostly cast, but have a small plate pressed in which is usually the weak spot of 1127-series oil pumps.
You'll see if this is the case when removing the clutch: a nice thick paste of sawdust, woodchips, bar oil and plain old dirt covering the oil pump is a telltale sign.
 
This guy does a good job with instructional videos for chainsaws. https://www.youtube.com/user/donyboy73

He has one for the oiler mechanism. Pretty straight forward.

------------------- edit -------------------------

Here is the oil pump replacement/fix video --
He's an excellent source. Clear close ups and with explanations and narrative.

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Thank you everybody for your insight.
yes I will take the take the clutch cover off the clutch drum off and check to see if the tang is broken
and I think I do know how to remove the oil pump if it's burstt
that's interesting that you've actually heard of it blasting out a lot of oil before it totally fails because that's what it did.
I'll check it either tonight or tomorrow night thank you very much.
Alright a quick follow-up post to let you
know what failed in case anybody cares thank you again
 
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