Originally Posted by JJY
Low speed needle too rich and idle gap too large. Lean low speed needle til idle stays high for 10-15 seconds then lower the idle with the idle gap screw. You will prabaly need to richen the high side a little after doing this as well.
+2 spot on.
its just a sign of the low end needle being rich. keep leaning the bottom end by small turns then have a long run to clean it out and bring it back. keep doing it until the idle stays at a contant high for around 20secs or more.
you will need to lower the idle screw as you lean out the bottom as the idle will raise because of the leaning.
when you have finished leaning the LSN and the idle is staying constant and you have a fairly good tuned HSN put a tank of nitro in and run it fairy hard til it reaches temp 90c+ and it is about half tank full and bring it back to you hard. when you stop it should stay a contant idle.
now you can try pinching the fuel line about 1 inch away from the inlet. it should only raise a couple hundred rpm then die. if it raises a fair amount and takes 5+ secs to stall its still too rich on the LSN. if it doesn't raise rpm and just dies quick then the LSN is too lean.
this is just a good test to make sure you havn't adjust the LSN too lean and possibly kill some glow plugs before races
what you have had is a high idle hiding the rich bottom end. once you have tuned it correct you will have a much cleaner punch and faster transition to your HSN which will in effect give you faster pick up...
once you have the pinch test to about 3secs and only a slight raise in rpm before it dies then you can run it on the track at race speeds around the slower corners and let it bog a little like other cars were around. drive it like that for a while let it fuel up if it is going to. come to a stop after doing the slower corner count to 5 then punch it hard. you can get the extra 5% of pick up by leaning if you find it still slightly over fueling and also better run time here as your getting the LSN a lean as possible while still being safe ont he motor so when your tapping it around the corners etc its now not wasteing nitro..
must have felt like typing