http://www.ofna.com/forum/viewtopic.php?t=4339
I have been typing my fingers off helping racers with the carb issues on the Hyper 8 port engines, and came to a realization that it makes more sense to type it one more time and make it a sticky for everyone to see...
The carb on the 8 port engine is a great carb, and I get frustrated when others say differently. The trick is to "know" the carbs needles, and the one that will get people every time is the midrange needle. There is a misconception that you should never touch the midrange, and I completely disagree. Learn how the midrange needle works, and adjust it accordingly...
The very first thing every 8 port owner should do is remove the entire high speed needle housing off of the carb body. Set the Midrange needle to flush with the carb body, and then look into the hole (where the high speed needle housing was) and look for the hole in the midrange needle, it must be in alignment with the high speed needle. The midrange needle has only 4 openings on it, so once you find the right location, all you'll have to do is remember that you can only make quarter turn adjustments on the midrange needle.Once you have the needle hole in the center, take a file and put a small scribe on the carb to make it obvious where the setting should be, and if it ever walks, you be able to quickly tell that its out of adjustment, and reset it...
I run the midrange needle 1/4 turn out from flush...
For my setup, the low speed needle will be sticking out from flush about 2.5-3.5 turns out...
Tune the engine a bit on the rich side on the bottom needle, and run it at about 250ish, and it will be a very fast engine....I like the Ofna PCR (#19789) pipe with a double bent manifold, and I use Mugen Alum. clutch shoes with Mugen 1.1 springs...
I hope this helps...
Have Fun...Burn Nitro...
This is a great help. But it sounds like something in your carb is messed up if the throttle slide is binding up. It sounds like you may have an air leak somewhere as well, be it inside the carb or the fuel tank/lines, I do not know. As long as I have the needles somewhere in the ballpark(to where it starts up so I can let it get to temp) I'm all set. One thing to realize though is that you have to go in VERY small increments. 1/4 turn is a huge difference. I'll bet your HSN is turning on your(from the vibrations) and changing your tune and/or there is air getting past the o-ring making it finicky. Get new o-rings for your carb and start back at square one.