Carb Questions

S

Speedle

Member
Hi everyone,

I am in my first season of LO206 Lights sprint racing and had some carb questions. I cleaned my carb today and followed the briggs guide for setting up my carb. Float height is set to .880", Float drop is set to 1.050", and my C-clip needle setting is set to the second position from the top. The idle air bleed screw has no affect on idle RPM. Should it? Also after my kart is warmed up and running on the stand I cannot get my engine to idle below 2000 RPM and when I press the gas pedal there is a hesitation. Is this normal?

Oh and I live in Colorado so my local track is around 5800' above sea level.

Thanks
 
The idle screw will set your minimum RPM. If it is backed out and still to fast then your cable probably dies not have enough slack. Some guys adjust the cable to set minimum RPM. Air bleed is for air/ fuel mixture overall and the needle effects mixture part throttle (off idle) your elevation is way different then mine so I won't even pretend to know what will work for you. Don't be afraid to try different things. Keep a note book so you know if your change helped or hurt...
 
I wouldnt be to concerned what it does on the stand. looks like you have good baseline steup. when you come off the track what does your plug look like. When you shut off your engine dont let it idle. shut it off as you come off the track like the Drag racers do in my opinon thats the only way to "read" a plug. Be aware though these engines do u run rich the trick is to find a happy medium. The briggs carb guide is good reference but dont be afraid to shy away from that especially at your altitude.
 
Thanks everyone! I plan on doing a test day soon to focus on some setting changes. One last question. What does float drop do? When going through my carb and checking all the settings, that was closer to 1.8" so I changed it to 1.050".
 
Speedle said:
Thanks everyone! I plan on doing a test day soon to focus on some setting changes. One last question. What does float drop do? When going through my carb and checking all the settings, that was closer to 1.8" so I changed it to 1.050".
Click to expand...
It's biggest purpose is to stop the floats from dropping so far that the inlet needle gets hung-up causing the engine to run full rich. If you ever see fuel coming out of your bowl overflow while the engine is idling, chances are that the inlet needle is stuck in the open position. Very common after trailering to the track, package dropped in shipping, or even a wheel hop or an off track excursion.


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🏁Thanks and God bless,
Brian Carlson
Carlson Racing Engines
Vector Cutz
www.CarlsonMotorsports.com
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Linden, IN
765-339-4407
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Hey everyone,

I just wanted to circle back. One of the guys at my last race helped me take my Carb apart and clean it really well. Even though there was light through the Emulsion Tube and jet, they were pretty gummed up. Once we cleaned those my engine runs so much better. It now idles around 1800 RPM and responds to adjustments with the Idle Air Bleed Screw. Thanks again for the help.
 
At 5k elevation you could try some things to lean it out a bit. Try going up one on the C-clip or going to. 900+ on the float. Turn the air bleed out a bit. Do one thing at a time.
 
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