Adjusting Needle Valve on Carburetor

Depends if you are running gas, or methanol.
For gas, the window is fairly small. a slight adjustment makes a large difference.

For methanol, the hole in the jet is the main concern. the needle is fairly far withdrawn from the jet hole, so it makes less of a difference. The main jet size is more critical.
Most start either at 1 1/2 turns from bottomed and tune from there.
 
Me too... 11/2 out from the seat and turn in or out in 1/4 turns for temp once I figure out the jetting it likes
 
Prokart88 said:
What do you look for to find the optimum rotation/location of the jet needle valve on the carburetor?
Click to expand...


Air/Fuel ratio on the dyno....but as the others have said, the main jet is your primary concern on alcohol. The needle does little to nothing. It's effective tuning range is from 1/2 to 2 1/2 turns out. Any further in cause intermittent fuel delivery. Any further out does absolutely nothing since the needle is already out of the fuel flow and risks losing the needle assy. onto the track.
Set it at 1 1/2 turns out and forget it. Tune with the jet.


-----
?Thanks and God bless,
Brian Carlson
Carlson Racing Engines
Vector Cutz
www.CarlsonMotorsports.com
Carlson Motorsports on Facebook
30 years of service to the karting industry
Linden, IN
765-339-4407
bcarlson@CarlsonMotorsports.com
 
You must log in or register to reply here.
Back
Top