laoban

I know most of the engine manufacturer will have a user guide on telling us how to reset to factory default HSN and LSN setting for a nitro engine.
I wonder what is the the defination of fully closed LSN and HSN ?

My understanding is, assume I run a test.

HSN test : The throttle is widely open. I blow the preasure line, if cannot see the fuel passing thru the fuel line to the carburator, or if I cannot hear any air flow sound, then the HSN is fully close .

LSN test : Assume the HSN is fully open, and the throttle is closed or released. I blow the preasure line, if cannot see the fuel passing thru the fuel line to the carburator, or if cannot hear air flow sound, then the LSN is fully close .

I am not sure if my understanding is correct or not. Please comment.

jonnymac

Just turn the needles In to their threads until you meet resistance (don't overtighten) then turn out from there.
You don't need to be blowing anywhere really.

DaveG55

All the carbs with needles that I'm aware of, car, motorcycle, lawnmower, jetski, whatever, work the same way. Turn the needle clockwise untill it just stops - as johnny said, don't overtighten it. Then turn the needle counterclockwise the prescribed number of turns for your base settings. That's it, no blowing, no throttle setting, nothing. Just turn it in till it stops then back it out again.