Nitrowoody1977

hi everyone just joined today to try and get some help with my bullet !!

i have a hpi bullet st nitro and bought it second hand all fine with starting and running apart from pulling off I'm running 25% nitro fuel ..... the car runs sweet flat out but struggles low down when I pull off it sounds like it bogs down slightly and then splutters when accelerating but the gos like a train flat out ? I've tried slightly adjusting the lsn both left and right but just can't shift that spluttering any help would be very welcome my idle is slightly high would this affect the tuning of the low speed needle ?
thanks dazzy

1QwkSport2.5r

Low speed sounds lean and/or idle gap too wide. Reset idle gap to .5mm, set low speed needle 1/2 turn lean of flush with the slide valve and set your high speed to about 3.5-4 turns out from lightly seated. Start engine and warm it up. Tune the high speed first for optimum power at WOT, then back off 1/8 turn leaner with tank about 1/2 full. Now tune low speed for a good low and stable idle. Once it will idle nice and low and steady for maybe 10-15 seconds, punch the throttle. It should be a little loaded up and blow a bunch of smoke and burble a little before cleaning out. If it flames out and quits, your idle is a tad too rich yet. Go back to the high speed - run a few WOT passes and listen to the engine when you let off the throttle. If the rpm hangs a little bit, the high speed is a little lean. Open it richer 1/16 turn and repeat WOT runs until the rpm doesn't hang. For all of this to work, your throttle linkage absolutely must return the throttle to idle and hold the throttle against the idle stop when you let off the trigger.