I found this:

Apparently there are two types of WT: Circuit Plate Type and Welch Plug Type. The first one doesn't need the tool, the second one does.
[Linked Image]
[Linked Image]


I am not sure what this all means but from the diagram above and photo below (taken from outdoorpowerinfo.com) my carb seems to be a Welch Plug Type. So it may need the tool after all.
[Linked Image]


However, there seems to be on line speculation that when you use the tool, the height of the lever arm comes to be flush with (if not very close to) the internal flat part of the carb around the lever. My carb has that flat section. I haven't yet tested this.

In regards to the distance (1.65mm), I didn't mean to imply it was wrong. In fact I found it is supposed to be between 0.060" and 0.070" You gave me 0.065" so you are spot on.

Had to edit to add this last pict showing the position of the straightedge for the WA WT WTA Welch Plug Type one. [Linked Image]

Last edited by grumpy; 06/02/14 05:30 PM. Reason: Add ubb to markup