sean

i have a NTC3 with an os.12tr. i have the stck gearing 1st gear 22p/54spur---2nd gear 26p/50spur. the drive train is nice and free,the engine has good compression and the car flies. BUT,when i nail the throttle from a dead start the car takes a few seconds to get going. i dont really know but it almost sounds like if you started out in a REAL car in second gear.it will go,but it takes a few seconds. i would think that a nitro car should be able to light the tires right up,not that i want to. anyhow i am new to the nitro game and dont know what i am doing. could it be my fuel/air ratio? does it sound like its to rich? there are several adjustments on the engine but the only one i have touched was the large needle valve on top of the carb-i leaned it out because it wouldnt reach high rpms. is there a different valve for low speeds? thanks ,sean

sean

btw,the fuel i use is 20%nitro and its fresh

teammpp

There should be another needle located in the end of the carb that the throttle linkage connects too. This is the LSN (Low Speed Needle) and I believe it is not in far enough making the bottom end rich. Turn it in 1/8th turn at a time and allow the engine to settle (run it around for a couple of minutes) before turning it in further.

Hope this helps.

sean

thank you for the advice. i appreciate it.

drfritz

if it's a tr with a slide carb theres are only two needle settings on the it,un like the novrossi type carbs that have three, high , low and mid range, any ways palmaris is correct in what to do, just was wrong as were to adjust, the low end sitting is in the back of the carb, were the mid range would be on most slide carbs. if it's a rotary carb then the low end setting would be on the linkage side of the carb.

teammpp

Thanks for the correction. I'm not familiar with the carb layout on the OS TR range hence my post as if it where in the normal location (thats my excuse and I'm sticking to it )

bbntc3

I've seen the same problem with at lot of engines, mainly after 3 to 4 mins run time, in those cases the Bottom needle is too lean. especially if the car runs good for the first 2 or 3 mins. Does your car do this? (runs ok for a few mins). If so before you adjust anything else richen bottom jet 1/2 turn,if that's good or worse go another 1/4 either way. then work from there. Once you get it close then start adjustly Bottom and main, 1/8 turns together to fine tune it. Hope this helps. Works with all my
modded engines.
People sometimes over look a lean condition at bottom due to a few things and your setting are really just misjudged. The setting you have and to much or less idle opening can really mess with the bottom performance seems too me this area is kinda overlooked sometimes. Just a thought! BB.