I use a Dynathrust 16/8 on my older G23, and idle below 2000 rpm. You may want to try a heavier composite (MA or ACP) prop over the wood one you are using. I also use Coleman's lantern fuel and Pennzoil 2 cycle aircooled oil at 32:1 with no treatment added or needed; fuel lasts forever. Many will argue against the use of low octane Coleman fuel, but the G23 is low compression and does not need higher octane.

Sincerely, Richard/Club Saito #635