Hi Andy,

Surely someone on here will respond, but if not I may be able to help.

I have an FS 26, and purchased a set of tools for that engine many years ago. I'm almost sure the tools for that engine will work on Larry's FS 20.

Lord knows where the tools are now, but I can probably find them given sufficient time to look. 

Let me know if you need them.

Bill

Well you need a metric allen wrench (as I recall) and these days it is almost impossible not to need a metric version so I'd recommend picking up a set at your local hobby shop or home improvement center.

I think I have just used a small crescent wrench to hold the jam nut.

Thanks guys.  Bob I don't believe the adjustment screw is 1.5mm, I tried my 1.5mm and it was to big.  I am guessing it is 1mm, but not to be a fool I will recheck it again.  Now that I know the jam nut is 4mm I will take the advise of others and make a call on my local hardware store.
Thanks All
Andy

Bob
Please accept my humble apology on the size of the adjustment screw, you are correct it is 1.5mm.  But the jam nut on the .20 I have are 5.5mm not 4mm.  It turned out I had everything I needed to adjust the valves.  I ran the motor today and it runs great.  I even called Larry, who has been under the weather for a couple of weeks, and let him hear the engine while it was running. 

I was getting 9K on a APC 8x6 and it ran a full tank with no problems.  I have to believe that it will only get better as the ring seats in with the cylinder.

To all that helped thanks very much, Bob your help was greatly appreciated and as I said before Frank Bowman was a great help in getting the ring installed.
Andy