Maytag model 72 twin help

Hi all, the Maytag  72 twin I purchased a few weeks ago runs, but according to the Maytag service book it is running too fast at around 1600 rpm ish , book says 1200 rpm,  to adjust  rpm`s  once small square plug is removed from crankcase top  and flywheel is turned there is a part that has a screwdriver slot shows in the hole  this needs to be turned clockwise to adjust speed to slow it down.

This is where I have a bit of bother as there are 2 parts with this screwdriver slot, when one is showing in the just over quarter  inch diameter hole other one is at 180 degrees away so when flywheel is turned  a  further  half a revolution the 2nd slotted part appears.

So can any Maytag 72 owners give me an idea as to how to tell which one I should adjust please as with engine running as it is do not want to do something that gives more problems as am sure people know how finicky 2 stroke engines can be at times.

I will add both slotted parts look identical  to me.

T I A    Don.

I have no personal experience of the Maytag 72, but did watch a complete rebuild of one recently.

Don't know if seeing one being rebuilt will help?

First in a series of videos

Hi Stuart, thanks for the video info, I had seen this series before, but did not see any info as to which was the correct part to alter for RPM change.
I sent an email to where I have bought parts for the other Maytag single I had a supplier called " Flywheel Supplies in the USA" the owner has just sent me a video of how to tell which of the two parts is the correct one to adjust so when time is available will be giving it a go.

Like has been said in other threads, the help that is given/offered with this forum is amazing.

Don