SHEEfan Posted March 9, 2011 Report Posted March 9, 2011 just got a new set of 38mm pwk's for my super cub, this is set up as a drag/all around duner..no porting on the cub, +4 timing, and vf2s!.. i got these carbs and they have a 165main, 55 pilot, and a cel needle on the 4th clip down........do you guys think this is a good starting point? or is it too lean? I know what the main and pilot jets change, but what does adjusting the needle up or down do?, how will this effect performance?? Quote
SuprSlow50 Posted March 9, 2011 Report Posted March 9, 2011 Please correct me if I am wrong but...The needle jet is responsible for 1/4 to 3/4 throttle, and maybe just past that where the main jet circuit opens up. The needle sits in the dump tube/main jet so the higher the clip is on the needle the less fuel it will allow up through the main jet and around the needle making it leaner. The opposite happens when you lower the clip, it pulls the needle up out of the main jet and allows more fuel into the motor from 1/4 to 3/4 throttle. There is also the length and taper of the needle that come into play, obviously, the thinner and shorter the needle is, the richer it will be. I am not sure about the jetting on your super cub setup, but for my 421 cub, I have 35mm pwk's and in the summer it has 155 main, 48 pilot, mixture screw 1.5 turns out, and CEL needle on the 3rd clip from the top. In the winter (-10-35degrees F) it had 165-170 main, 52 pilot (too big but didn't have 50's) mixture screw 2.5 turns out. My jetting may not be of much help but I figured I would list it for you anyways, I'm sure someone else will be able to help. Quote
SonOfSand Posted March 9, 2011 Report Posted March 9, 2011 I think those are all good staring points, except the pilot. I am pretty sure it will be rich. I don't own a cub though. I would dial in the pilot first. Quote
SHEEfan Posted March 9, 2011 Author Report Posted March 9, 2011 thanks for the responses guys. that makes sense with the needle and i think i will leave on the 4th clip until i take it out and run it, yeah i think the pilot may be a little rich, i will probably put a 50 pilot in them and see how that goes..? Quote
sleeper06 Posted March 17, 2011 Report Posted March 17, 2011 i know a reg cub would jet much higher like 178-185 dep on elevation but im not sure how a super cub pulls fuel Quote
SHEEfan Posted March 17, 2011 Author Report Posted March 17, 2011 much higher even on a unported cub? ....my supercub is unported just cleaned up Quote
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