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Stihl MS390 not oiling the chain

Discussion in 'Mechanic and Repair' started by Pecker, Sep 18, 2005.

  1. Pecker

    Pecker LawnSite Bronze Member
    Posts: 1,454

    Hi what's up. I'm hoping someone can offer some advice please. Here's the deal - it is using roughly half the reservoir of oil per fuel tankful (about right I think), but there is not nearly enough oil getting on the chain. When I run the saw WOT with the nose of the bar close to a light piece of wood (like you do to see if it is oiling properly) the chain is not throwing any oil. I have adjusted the oil screw on the bottom to full open and it isn't enough.

    Here's what I've done in attempt to remedy the situation: I took the bar off and made sure the oil hole on the power unit was not clogged. The blew out the hole in the bar where the oil goes in with high pressure compressed air. It worked a little better until I started sawing again and now it is not oiling again.

    Also, I clean the saw, sharpen the chain by hand, fill up the fuel tank, fill up the oil tank every tankfull. I'm meticulous with maintenance. And the chain has about 4 tank fulls on it so its not old at all. The saw came with a Stihl green bar but I put a Stihl yellow bar on it - but the oil hole seems to line up properly.

    Any and all advice welcome and I'll try it because I really don't want to send it to the shop for something like this. Thanks in advance.
  2. bill w

    bill w LawnSite Member
    from Va.
    Posts: 198

    Have you tried cleaning the bar groove? If not, as soon as you start cutting again the crud will move to block the oil hole.
  3. Pecker

    Pecker LawnSite Bronze Member
    Posts: 1,454

    Yeah, I clean the bar groove and blew the hle out real good with compressed air. It worked ok for a few minutes and then stopped oiling again. Is there any way to make the oiler unit on the saw put out more oil beyond opening the screw al the way? How does that unit work? Thanks.
  4. bill w

    bill w LawnSite Member
    from Va.
    Posts: 198

    I believe I'd clean the oil pickup and tank as the next step. I know of no way to adjust the oiler any further.
  5. Pecker

    Pecker LawnSite Bronze Member
    Posts: 1,454

    I've never been into that part of the saw. Is there any to it? How do I get to the pickup? Thanks.
  6. lwcmattlifter

    lwcmattlifter LawnSite Senior Member
    from NC
    Posts: 859

    If you can, drain the oil tank and remove the oil pickup assembly for cleaning. How long is the bar your using? These saws aren't known for spectacular oiling systems. You may find that going with a shorter bar will help.
  7. joe stihl

    joe stihl LawnSite Member
    Posts: 35

    Some of the MS290,310, 390's have bad oil pumps from the factory. If it's still under warranty, take it in and have it replaced.
  8. Restrorob

    Restrorob LawnSite Fanatic
    Posts: 11,023

    The E.P.A. has come down on saw manufacturers the last few years and have made them reduce the amount of oil dispersed onto their chains.
    For that reason you can no longer put a bar near a block of wood and see oil being slung on it. As long as your chain is not burning up or turning blue from lack of oil I see no reason to worry about it.
    If you did take it to a shop all they would do is remove the bar start it up and check for a little dribble out of the hole and tell you nothings wrong.
  9. Pecker

    Pecker LawnSite Bronze Member
    Posts: 1,454

    The bar is 20" long. I'll clean out the oil tank next.

    Is the pickup something I can clean or do I need to replace it?

    Where is the oil pump located? Anything to replacing it?
  10. Pecker

    Pecker LawnSite Bronze Member
    Posts: 1,454

    That's what I don't want to happen. payup

    How high does the engine have to rev for the oiler to dribble oil? I'm afraid of doing engine damage by running it with no chain. . .

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