Ms290 refuses to oil

[RED-85-Z51]

Guy brought it in about a year ago not oiling. I put on an aftermarket oiler and it oiled okay but not the usual texas oil well from a 290 but it was just enough. Thru the year ive watched it have oil issues but it never hurt the bar or chain. So now it barely oils. I flushed the tank, blew out the vent, new filter and hose, oem pump, worm gear and inspected/blew out the feed line.

It oils just a bit...but 10s wide open its a faint line on the shop floor.

The pump is maxxed out.

Bar is clean.

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[Wood Doctor]

Try the same bar and chain on another saw that accepts it. See if that saw does the same thing and check that saw's bar and chain on this 290. (ie. swap and compare)

 

[RED-85-Z51]

Try the same bar and chain on another saw that accepts it. See if that saw does the same thing and check that saw's bar and chain on this 290. (ie. swap and compare)

It barely oils with the bar off. Like barely a dribble wide open.

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[trains]

put on a new oem oiler and test.

Was marginal when you first fitted it as you mentioned in your first post.

assuming the oil pickup hose is not allowing an air leak, and thus drawing/ pumping less oil.
Or the O ring beneath it is not doing the same.

 

[RED-85-Z51]

put on a new oem oiler and test.

Was marginal when you first fitted it as you mentioned in your first post.

assuming the oil pickup hose is not allowing an air leak, and thus drawing/ pumping less oil.
Or the O ring beneath it is not doing the same.

Has a new oem on it, also tried a new aftermarket one i had. I pressurized the system lightly and noted no leaks at the plastic elbow or its orings...nor the rubber inlet elbow. It pumps...but its so light and sporadic...it acts like its sucking air but i don't see where from.

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[trains]

sorry, I miss read your post, thought you said you put an after market one on, and it oiled less, then seemed to get less and less oil over time, just re read, and saw where you fitted the oem one, my bad.

Rubber can be odd at times, and hold/ work under pressure, but due to cracks etc, can draw air when vac is applied, O rings in particular can be prone to this.

Have you taken off the elbow, and inspected the O ring, or replaced the o ring ?

Whilst thats off, has the pump actually moved in the housing orientation and depth, worth double checking whilst there (unlikely, but worth confirming).

my bet would be on a crack in the o ring, then where the elbow barb fits the oil pick up hose.
Then pump orientation.

I am assuming that you didnt replace the o ring when you did the pump, even tho you did replace the oil pick up hose, and is that oem ?
its not mentioned in your original post.

I am also assuming the pump is not blocked again due to a dirty oil tank, and crud getting past the filter screen and lodging in the inlet tract of the oil pump.

 

[Timber MacFallen]

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

 

[RED-85-Z51]

I blocked the outlet and pumped 15psi into the tank, it held about 30 seconds with no leaks until my plug blew out and shot a half tank of bar oil into the air.

Im going to put it in wood tomorrow...see what it does. Its definitely not leaking

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[jr27236]

I blocked the outlet and pumped 15psi into the tank, it held about 30 seconds with no leaks until my plug blew out and shot a half tank of bar oil into the air.

Im going to put it in wood tomorrow...see what it does. Its definitely not leaking

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Maybe this chainsaw just wanted to get a money shot in and would rather its bar put in something other then wood to lube? Just saying [emoji23]

 

[OddSawz]

Is there a valve going to the oil tank? Could be under vacuum.

 

[dmb2613]

there is an oil passage leading to the front of the saw, Is it leaking where it is plugged

 

[RED-85-Z51]

The way it works is there is an oil inlet hose/grommet in the bottom of the tank, accessed by removing the loop handle, its new and clear. Oil goes into the bottom of the pump then out an elbow into a junction to the outlet to the bar mount pad. Its all clear, no leaks under 15psi, the check valve works correctly. I put it in wood...the chain never looks wet but it oils just enough to keep it happy, probably 3:1 gas to oil. The bar has at least 30 tanks thru it and the paint is intact...so its not burning it. Its not "right" but i cant get it any better.

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[Wood Doctor]

Try thinning the bar oil a little. When it's this cold outside, I usually add a couple ounces of mixed fuel per tank of bar oil. My 390 oil pump loves that.

You said 3:1 gas to oil? I think you meant 3:1 oil to gas, right?

 

[RED-85-Z51]

Try thinning the bar oil a little. When it's this cold outside, I usually add a couple ounces of mixed fuel per tank of bar oil. My 390 oil pump loves that.

You said 3:1 gas to oil? I think you meant 3:1 oil to gas, right?

Its running about a 20% blend of 10w30 and Amsoil bar oil. It gets about 3 tanks of gas to 1 tank of bar lube

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[Wood Doctor]

Its running about a 20% blend of 10w30 and Amsoil bar oil. It gets about 3 tanks of gas to 1 tank of bar lube

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OK, now I see what you mean. Mine uses about 2 tanks of fuel to one tank of bar oil, 20" bar. So yours might be a little slow on oil release. Cold weather does slow it down and that's why I usually thin the bar oil a bit when we start looking at single digits.

 

[RED-85-Z51]

OK, now I see what you mean. Mine uses about 2 tanks of fuel to one tank of bar oil, 20" bar. So yours might be a little slow on oil release. Cold weather does slow it down and that's why I usually thin the bar oil a bit when we start looking at single digits.

Its 60 here today. Supposed to hit 21 this time next week

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[Wood Doctor]

Its 60 here today. Supposed to hit 21 this time next week

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All you have to do is send all that weather to eastern Nebraska. Our vacation from a cold winter ended this week. We have returned to normalcy. More snow is on the way also. The weathermen around here amaze me. A they forecast deplorable cold and snow, they smile like Bozo the clown.

 

[SteveSr]

Has a new oem on it, also tried a new aftermarket one i had. I pressurized the system lightly and noted no leaks at the plastic elbow or its orings...nor the rubber inlet elbow. It pumps...but its so light and sporadic...it acts like its sucking air but i don't see where from.

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New OEM as directly from the dealer or used? I have seen multiple occurrences of Stihl oil pumps that get crud stuck in them from the tank which causes the symptoms that you are describing. Pumps oil but not enough. Some pumps can be disassembled and cleaned some cannot. The issue is that the pickup in the tank is a coarse screen and not a filter or oil wouldn't flow through it. This leaves a way to get smaller stuff into the pump. Some of this may flow through while other might get stuck.

 

[RED-85-Z51]

New OEM as directly from the dealer or used? I have seen multiple occurrences of Stihl oil pumps that get crud stuck in them from the tank which causes the symptoms that you are describing. Pumps oil but not enough. Some pumps can be disassembled and cleaned some cannot. The issue is that the pickup in the tank is a coarse screen and not a filter or oil wouldn't flow through it. This leaves a way to get smaller stuff into the pump. Some of this may flow through while other might get stuck.

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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[SteveSr]

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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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.