026 oiler pumping air bubbles

[heartofdarkness]

I have an older non-pro 026 (~1996ish, with the adjustable carb) whose (nonadjustable) oiler isn't oiling. Rather than a continuous adequate flow of bar oil, it pumps a small trickle of oil sporadically and air bubbles every three or four seconds; the bubbles are about the diameter of the oil tube where it meets the bar. A large puddle of bar oil is collecting around oiler proper, but I can't see an obvious source of the leak.

The air bubbles might be caused by a tubing crack somewhere upstream of the oiler, allowing air to be sucked in rather than oil, causing the pump to cavitate. But if oil is being pumped into the clutch area, then oil is being successfully pumped (so the upstream tubing is viable), but where are the air bubbles coming from, then? Maybe a leak within the oiler proper? The tubing between the oiler and the bar seems to be sound.

Any wisdom out there to be bestowed?

I've done several searches, but haven't found any mention of this.
Thanks.

 

[treeclimber165]

Sounds like a bad O-ring on the pump where it mounts against the oil resevoir.
Pull the sprocket/clutch assy so you can get to the oiler. Clean the entire area around the oiler thoroughly. Remove the two torx head screws holding the oiler in place and lift the oiler off. At the bottom right side is where the O-ring/ grommet seals against the oil tank.
While you have it off you can clean out the pump to remove any debris that might have collected over the years.

You might also check the oil pickup and tube while you have it apart.

 

[stihltech]

oiler

Is this a plastic pump? If so, look just below the outlet on the pump itself.There will be a small open hole. The plug in this hole has fallen out.
Find the correct size machine screw that will thread into the hole. There are not threads there now, but the screw will make it's own. Use some blue loctite on the screw, and install the pump.
Common problem on this saw, but an easy repair.