I use a 1974 40 Featherweight, which I have converted it to run on a 25:1 mixture by fitting a no 2 needle, on my 7ft dinghy. I find that to get it to run smoothly without 4-stroking I have had to screw the mixture adjustment down slightly more than 2½ turns below "flush".
Is that OK?
Even a ¼ turn less and it tends to 4-stroke when lightly loaded.
I use an TCW3 outboard oil, currenly it is Quicksilver.
40 Featherweight mixture adjustment
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