Stihl 026 (Older) Tower Tank Vent

[worshipguitar]

Evening Friends,
What is the purpose of the set screw at the very top of the tower tank vent on the older 026's? My saw runs great screwed all the way in, all the pictures I see show the same
thing, yet my Stihl dealer tells me it should be backed out a couple of turns. He's got me puzzled. Thanx for all the help..........

 

[windthrown]

I always ran them with those screws all the way in. The service manual for the 026 does not specify a loose screw. They call it a self-tapping screw.

 

[kevin j]

Don’t turn it in like a screw, just push it in. If you screw it in, it cuts threads in the plastic and pretty much seals. It needs a spiral air path around the threads to create the vent. I think it’s just about a 1032 size setscrew

 

[Mad Professor]

I think it just acts like a grub screw used in fuel line type tank vents