Echo carb adjustment tool for 501 and 620?

[motoguy]

I've been trying to adjust the carbs on my saws, and I'm having a bear of a time adjusting them with small flathead screwdrivers. Once the saw starts revving up and vibrating, my flatheads are falling out of the slot. I've done a search for "echo carb tool", but I'm not finding one that looks like it would work on my saw. It's basically a circle, with a slot cut through it. I thought I might find some sort of a tube (to slide over the shaft) with a "cross bar" inside, to turn the shaft. The little splined unit for my old Poulan made carb adjustment a breeze.

Can anyone point me to the tool I need to make carb adjustment easier on the Echo saws?
Thanks!

 

[Woodanhor]

Its a splined tool also
Goes around screw and grabs the serrations