Stihl 009L oiler issue

[bcsman]

So had my Stihl 009L for many years. Haven't had any real issues until a week or so ago. Generally it goes thru a tank of fuel and oil. Last week it only used a half tank of oil so figured better take a look. I know there are no parts for this problem but wanted to take mine apart. Everything part wise seems to look good, I took a pic of them broken down. I was able to blow air from the black hose to where the oil comes out. My question, is there a vent somewhere that may be blocked and where is it located? I also have a pic of the pump area. Any other things to look at would be appreciated. Thanks for any help, the bad thing is it stills runs great....

 

[trains]

There is a ball and spring beyond the plunger pump rod in the brass bit on the top right of the first pic, (there should be a filter over that brass thing as well, ususally foam that slowly disintergrates), , sometimes they get a bit gunked up and the ball sticks to its sealing base, or bits of sawdust gets in there and it wont seal, and thus wont pump.
if the diaphragm is damaged, your out of luck, you cant get the part anymore, so be really careful.
impulse signals from the crank act on the other side of the diaphragm and cause it to pump.

 

[Vintage Engine Repairs]

There is a ball and spring beyond the plunger pump rod in the brass bit on the top right of the first pic, (there should be a filter over that brass thing as well, ususally foam that slowly disintergrates), , sometimes they get a bit gunked up and the ball sticks to its sealing base, or bits of sawdust gets in there and it wont seal, and thus wont pump.
if the diaphragm is damaged, your out of luck, you cant get the part anymore, so be really careful.
impulse signals from the crank act on the other side of the diaphragm and cause it to pump.

I smiled when I saw you had replied as I was about to tag you in this post

 

[StihlSolo]

The port / hole at the red arrow leads to a tunnel that ends up at the bottom of the crankcase. The tunnel is shaped square and is cast along the joint between crankcase halves and is gasketed along that length. The port at the crankcase bottom is square.

As said, this port and tunnel acts like an impulse line for the pump diaphragm

If saw is run rich (easy to do with this 009-012 series), fluid could accumulate in that tunnel and could restrict impulse flow.

Try this. Take out spark plug, and GENTLY blow out that tunnel starting at that red-arrowed hole. Not too much air: if you blow out the gasketed portion, you’ll have bar oil seeping into the crankcase.

And you do need that foam filter as mentioned earlier.

 

[bcsman]

There is a ball and spring beyond the plunger pump rod in the brass bit on the top right of the first pic, (there should be a filter over that brass thing as well, ususally foam that slowly disintergrates), , sometimes they get a bit gunked up and the ball sticks to its sealing base, or bits of sawdust gets in there and it wont seal, and thus wont pump.
if the diaphragm is damaged, your out of luck, you cant get the part anymore, so be really careful.
impulse signals from the crank act on the other side of the diaphragm and cause it to pump.

Is this ball and spring you are talking about where the thin diaphram rod slides into? And how do I check it? I have pushed a thin piece of wire down there and seem to be pushing a spring when it bottoms out.

Also if I hold the diaphram up to the sun I can see light thru it, not directly but filtered. Should there be any light showing thru it, if not then it's bad.

 

[trains]

Is this ball and spring you are talking about where the thin diaphram rod slides into? And how do I check it? I have pushed a thin piece of wire down there and seem to be pushing a spring when it bottoms out.

Also if I hold the diaphram up to the sun I can see light thru it, not directly but filtered. Should there be any light showing thru it, if not then it's bad.

Yes, its beyond the pump rod, or thin rod as you call it, if the ball is stuck on the seat, or if there is saw dust/ debrits under the ball, and it wont seal, then it wont pump.
gentle air pressure, put some hose on the end of the brass bit, and blow with your mouth, and suck, check for positive seating of the ball.
some gentle moving with the wire and air can dislodge and remove the debrits causing the problem.
diaphragm can get thin, but its whether or not its air tight is the key.

 

[bcsman]

The port / hole at the red arrow leads to a tunnel that ends up at the bottom of the crankcase. The tunnel is shaped square and is cast along the joint between crankcase halves and is gasketed along that length. The port at the crankcase bottom is square.

As said, this port and tunnel acts like an impulse line for the pump diaphragm

If saw is run rich (easy to do with this 009-012 series), fluid could accumulate in that tunnel and could restrict impulse flow.

Try this. Take out spark plug, and GENTLY blow out that tunnel starting at that red-arrowed hole. Not too much air: if you blow out the gasketed portion, you’ll have bar oil seeping into the crankcase.

And you do need that foam filter as mentioned earlier.

Good news, I took your advice and gently blew thru the vent hole with the spark plug out and all of a sudden she's pushing oil out again. Hard to say how long it will work but for the time being she lives!! Thank you so much for your advice, have never heard of doing this with the 009L oiler issues. Bet there are some in the junk that could be saved with this fix. Again thanks so much my friend.....