Chris wrote:
on a 1968 Johnson 20hp there is a lean - rich mixture knob. beneath the
knob's limits (9 back to 3 o'clock) there is an awful lot of room for
adjustment. I'd like to set this motor back to what the factory would have
set it to, but I have no way of knowing what that is.

I'd say from where it is positioned now to remove it more than 15 turns
could be done. I didn't check how many more turns to put it all the way in
though.

thanks to anyone who may have the correct settings (how many turns out I
assume for original settings).




The "factory' setting is rarely correct for almost 40-year-old outboards.

The idle mixture can be adjusted within a limited range by turning the
external knob and shaft. To accurately set idle mixture, pull lever/knob
(depending on model) from end of needle. Turn needle in until it seats
lightly, then back out one(1) turn. Start and run motor until it reaches
normal operating temperature, then turn needle to provide smoothest
operation while idling in forward gear. Clockwise rotation of idle
mixture needle leans the mixture, CCW to richen. Press lever/knob back
on end of needle in center of travel, being careful not to change needle
setting.

High speed mixture is controlled by the size of a fixed main jet.

Rob