Weak oiling on Stihl 028 AV Super

[kst8engineer]

I'm trying to troubleshoot a weak oiling system on my Stihl 028 AV Super. The filter screen in the oil tank appears to be clean, and the worm gear and drive sprocket are in good shape.

What should I check next? Should I remove the pump and try to blow air through the line to the oil tank? Is there a way to determine whether the pump itself is bad or not?





Thanks in advance!

 

[drf255]

I'm having the same problem. Interested in the responses.

 

[kst8engineer]

I found another thread discussing a similar issue on an 028 WB: http://www.arboristsite.com/community/threads/oiler-adjustment.7708/

In that post, Stihltech stated the following:

"Look for 2 things. A worn oiler gear, or a loose pin in the bottom of the pump. Either will cut the output down.
Don't forget to clean all passages, especially the ones UNDER the pump gasket."​

I'm not sure off-hand what the pin is that he's referring to here, but I'll plan on pulling the pump off tonight to check it out.

 

[kst8engineer]

I pulled the pump off this evening and blew some brake parts cleaner through the passages below the pump as well as some compressed air. A little bit of gunk flushed out of the port between the pump and the bar, so I'm hoping that'll help.

Regarding the pin inside the pump, there's a small amount of axial play between the pump shaft and the pin, but not much (just eyeballing it, maybe 030"). Is that within acceptable limits?

 

[Wood Doctor]

When you removed the bar, chain, and cover, and then ran the saw for a minute at half speed, did any bar oil come through the port and slot where it oils the bar? It should have. If it did, then the oiler is OK.

In your first paragraph above, I have done that as well and it usually works to get the gunk out.

 

[kst8engineer]

Yes, I get a very small amount of oil coming out when I run it without the bar/chain/cover, but I don't think it's pumping the volume that it should. When I run with the bar and chain installed, it doesn't visibly throw any oil at all. I'll reassemble it and see if the brake cleaner and compressed air did the trick.

When you removed the bar, chain, and cover, and then ran the saw for a minute at half speed, did any bar oil come through the port and slot where it oils the bar? It should have. If it did, then the oiler is OK.

In your first paragraph above, I have done that as well and it usually works to get the gunk out.

 

[Wood Doctor]

Yes, I get a very small amount of oil coming out when I run it without the bar/chain/cover, but I don't think it's pumping the volume that it should. When I run with the bar and chain installed, it doesn't visibly throw any oil at all. I'll reassemble it and see if the brake cleaner and compressed air did the trick.

One other thing to check. Make sure that the oil hole on the bar lines up with the slot in the case that dispenses the oil from the pump. On occasion, they fail to do so. I ran into this on a 290:

In the above case, less than half the oil made it to the bar.

 

[Cope1024]

Yes, I get a very small amount of oil coming out when I run it without the bar/chain/cover, but I don't think it's pumping the volume that it should. When I run with the bar and chain installed, it doesn't visibly throw any oil at all. I'll reassemble it and see if the brake cleaner and compressed air did the trick.

My MS2190 doesn't always throw oil off the bar, but when I check it, the bar and chain are wet.

 

[Wood Doctor]

My MS2190 doesn't always throw oil off the bar, but when I check it, the bar and chain are wet.

I agree there. You would be surprised at how little oil is required and that many saws over oil the bar.

 

[kst8engineer]

I put it back together after cleaning the passages under the pump, and it seems to be working well now. Thanks for the good advice!

Another unrelated issue:
The master lever on my saw has 4 positions - off, run, start, and choke. My saw immediately dies when I switch it from the "start" position to the normal "run" position, just like I had switched it off.

Does the "off" position ground out the magneto to kill the engine? I wondered if the lever mechanism might be somehow messed up, causing it to ground the magneto out in the "run" position by mistake. Alternatively, would you suspect the carb is out of tune (lean?) causing the engine to need to be partially choked in order to run?

Thanks again

 

[Wood Doctor]

I put it back together after cleaning the passages under the pump, and it seems to be working well now. Thanks for the good advice!

Another unrelated issue:
The master lever on my saw has 4 positions - off, run, start, and choke. My saw immediately dies when I switch it from the "start" position to the normal "run" position, just like I had switched it off.

Does the "off" position ground out the magneto to kill the engine? I wondered if the lever mechanism might be somehow messed up, causing it to ground the magneto out in the "run" position by mistake. Alternatively, would you suspect the carb is out of tune (lean?) causing the engine to need to be partially choked in order to run?

Thanks again

If it immediately dies, then it sounds like an electrical problem and the switch needs adjusting. Remove the cover and air filter. Note the black wire position. In the Run position, there should be about 1/8" gap between the end of the wire and the flat spring switch that connects to ground. That gap must be there or else Run will kill the engine.