Chevy,

I am rigging a cable linkage for my TT 75 4-stroke on my Neptune seaplane. RCKen has a great idea if you have room, but I have the additional constraint of getting mine to fit in the cowl. This is important as I need to keep spray off the engine as much as possible. The cable (goldenrod brass cable) runs through the firewall just like yours. What I did was mechanically adjust the linkage for minimum travel by using the innermost holes on the carb linkage and electronically trim the servo to give me the required throw. I'll post a picture later, but you could practically walk to my house from yours and see it yourself.