Ms290 refuses to oil

[RED-85-Z51]

Have you tried running it without the b & c? Set the saw horizontal as in cutting position and watch the oil flow coming out of the bar mount hole. Any bubbles indicate that the pump is sucking air from somewhere.

Yep...same result as with the cutting gear on...it oils, just not much


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[Jasonrkba]

Sounds like the leg of the worm gear is slipping out of the notch on the drum.

 

[SteveSr]

Sounds like the leg of the worm gear is slipping out of the notch on the drum.

That could do it too especially if the clutch drum or bearing are worn enough to wobble. You should also see the end of the worm lever is worn where it has been slipping out of the notch in the drum. It does have the correct notched drum, doesn't it? I think that the only Stihls that had this possibility were the 026/260s Pro/non-Pro.

 

[RED-85-Z51]

The notch is present and there is a visible amount of post that slips out beyond the edge, no signs of slippage. I even made sure it was level and not pushed down any letting it drop out. Its bizzare...

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[Jasonrkba]

Sounds like all the components of the oiling system have been replaced. That is strange. Maybe disconnect the hose on the bottom and see if it will flow to that point.

 

[Jasonrkba]

I just remembered something i delt with one time. If you remove the muffler there is a plug in the case on the left. Usually orange if its missing oil will go there instead of the bar.

 

[Jasonrkba]

..

 

[RED-85-Z51]

..

Yep dealt with those in the past, its intact and present.

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[kuhndog]

Maybe the plug is set too far and blocking the passage ?

 

[stihl86]

I soaked the tank in gas to make sure it was clean. Then put on a new hose, filter, and oem pump from the dealer...i was done playing and accepted id have to eat some cost to get it done right and just keep the customer happy. But..no real improvement.

It oils...the whole system holds 15psi with no leaks and vacuum too. It could oil..more.

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The tanks have vent. They should not hold vac.

 

[SteveSr]

The tanks have vent. They should not hold vac.

With the tank empty and open I usually spray WD-40 through the vent from the outside in. I suppose you could also use carb or brake cleaner and then follow up with air. These are usually just a metal disc on a metal seat.

 

[RED-85-Z51]

The tanks have vent. They should not hold vac.

I was using the vent as my access to the system.

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[stihl86]

I was using the vent as my access to the system.

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So how does that check the vent? You said it holds vac and pressure. It would make more sense to check the supply side from the oil suction hose at the pump end.
Vac 1st, then pressure. Vac should bleed down if vent works. Pressure should not.

 

[cookies]

i recently dealt with this on my ms290...replaced the pump/line/pickup then cleaned the vent and tank..ended up being worn worm gear threads and its brass bushing allowing it to slightly cock under load/rpm pulling the threads of the worm gear away from the oil pump. Looking at the old part next to the new part i couldent really see enough wear to think it was cooked, i condemned the new worm gears arm out of the package being it did not grip the worm gear firm enough and seemed bent away from the clutch drum enough to not ride in the top of the notch. These pumps are able to be disassembled by removing a roll pin to be repaired/cleaned.

Has anyone modified a pump by disassembling and removing more material from the notch/pump to gain more oil volume? these ms 290s seem to barely put out enough oil to run a 18-20" bar when functioning properly set at max output.

 

[SteveSr]

I was using the vent as my access to the system.

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I am afraid that I don't understand how you did this. Was the vent removed? Did you just hold a piece of hose on the end of the vent? Photos would help. If the vent was still in the system it could still be clogged and your test wouldn't show it.

 

[SteveSr]

Has anyone modified a pump by disassembling and removing more material from the notch/pump to gain more oil volume? these ms 290s seem to barely put out enough oil to run a 18-20" bar when functioning properly set at max output.

Can you retrofit a pump / piston from a 390 pump? I would hope that it could move more oil.

 

[cookies]

pretty sure they are the same pump part #

 

[DND 9000]

Yes these MS 290, 310, 390 oil pumps use the same pump piston. But you should know if you have the older style oil pump or the newer one. The pump pistons don`t interchange between these 2.

 

[LordOfTheFlies]

Any chance it's the problem DonyBoy points out on this Stihl at 1:20:

Hey man. Thanks for this post. This happened to me just now. 029 was oiling intermittently and lol and behold the worm gear was indeed shot with the metal part spinning around the plastic gear. $20 at the dealer and fixed and working properly now. Thank you!