The LSN controls fuel flow from idle to mid-open throttle, say, dead stop to half throttle.
The HSN handles mid-throttle to WOT.
The worst thing you can do, both for your sanity and for the life of your engine, is try to tune both needles at the same time! You're asking for problems.
Best thing you can do right now, is, set your needles back to factory. Once you've done that, start tuning your HSN first (and ONLY your HSN right now.) You're looking for a temperature in the 220-230 range, a good smoke trail and your rig running nice and smooth from mid throttle to WOT. Once you've gotten to this point, and ONLY when you've gotten to this point, you can start tuning the LSN.
The LSN will control the 'jump' you refer to. Goal is to be able to nail the throttle and your rig get up and go! Once you've tuned the HSN, start dialing in the LSN clockwise in 1/8th increments until you reach the preformance you are looking for. If you nail the throttle and it gurgles and sputters, turn it clockwise. If you nail it and it flames out suddenly, you are too lean, turn it counter-clockwise. Once you have it to where you think it should be, give it the pinch test. It's really easy, pinch the fuel line to the carb and starting counting "one, one-thousand, two, one-thousand..." until it shuts down. If you got anywhere from 3-5 seconds, your LSN is dialed in. If it cuts off before 3, you may be a bit too lean, still. Anything over 5 and you may be a bit too rich. It may not be scientific, but you'll see a lot of folks here swear by it!
The crucial thing to keep in mind throughout all of this is.....PATIENCE! You keep jacking with the needles every 10 seconds you'll go crazy and be nothing but pissed off! Like Sweetdiesel said, give yourself 30-45 seconds of run time in between adjustments. That does not mean 30-45 seconds of idle time! You have to run it! I usually count 8 to 10 passes of about 150 feet before I bring it in to adjust and I work to go through the entire throttle power band.
Don't get too wrapped up on molecules being formed and where they go. Just take it one step at a time. Once you get it down, it'll become second nature, but you have to be patient and learn to understand what the mill is telling you it's doing. You just have to learn its language!
Have fun with it! Keep posting with any problems and don't forget to use the search function. I think if you search 'tuning' in the power plants forum, there is a great article on how to tune. I'll try looking as well and if I find the link, I'll post it here.
