Carb TILT

kepner

Member
Wouldn’t “tilting” the carb forward using the slot “lean” the fuel (no pun) and tilting backwards be richer setting? The floats are on a fixed axis and the jet is centered. Seems for instance tilting all the forward would move fuel to frontal part of bowl and when the slightest amount of fuel ALSO TOUCHED back float it would begin the process of shutting off fuel sooner then if the carb were level. And opposite for backward tilt.
 

kepner

Member
:). Can you explain it not so simply. Seemed like it would when carb apart and gas in kitchen bowl watching and testing By hand tilting carb. And primitive test I must admit. I see thru mountable carb bowl would be easier.
 
The fuel in the bowl is the available supply for the jets, which are what meters the fuel flow. Without altering the size of the jets or air bleeds the air/fuel ratio won’t change.
 

Ted Hamilton

helmet painter and racer
^^ That's true, but if the jets are partially starved, a higher float level will supply more available gas, leading to a practically richer mix. The ratio of delivered mix will remain the same, but there will be more mix available. Once the jet runs out of fuel, the engine's still pulling air, leading to an "apparent lean" condition.
 

95 shaw

Premium User
The fuel level controls how far the carb signal has to lift the fuel.
Less fuel in the bowl means the fuel has to be lifted farther.
 

Kart43

Member
The fuel level controls how far the carb signal has to lift the fuel.
Less fuel in the bowl means the fuel has to be lifted farther.
That is correct. The fuel weight plus the atmospheric pressure on it causes it to be higher in the fuel pick up tube.
 

kepner

Member
So does leaning and tilting carb 15 degrees approx cause less fuel in the bowl and if so, with less fuel in the bowl making a difference as described by some above on the leanness or richness of A/F, especially at higher rpm?
 

kepner

Member
SOME posts have said elsewhere to level the carb on 206 using slot. If it makes no difference then one must ask “why make sure its level?”
 

95 shaw

Premium User
SOME posts have said elsewhere to level the carb on 206 using slot. If it makes no difference then one must ask “why make sure its level?”
When asking for help/ advice, best results can be expected if consistent with the method used by the one giving advice.
Going your own way can pay dividends sometimes, just need to know that is the case, when getting, or giving, advice.
 

Kart43

Member
When you attempt to level the carbit is not aligned with the intake tube, there is a considerable step, and obstruction at the transition.
 

CarlsonMotorsports

Premium User
Even with a 15* mount, you can level the carb considerably more than 15.*
Having the carb mounted on an angle would change the float height because the bowl of the carb is also sitting at an angle, while the fuel would sit level. One side of the float would carry more of the weight of the float set.
The fuel height in the bowl not only affects the height from which the fuel is pulled up through the jets, but also plays into the e-tube. (higher vs lower fuel levels)
Now, all that considered, as soon as you fire up the engine (idle) much of the fuel is in the air and not all in a pool in the bottom of the bowl.
It's not hard to see -- just take an extra bowl and cut a hole in the side of it, then epoxy on some clear glass. If you do it on one side of the bowl, all you will see is the side of the float - but that's not all bad because you can also see the fuel level clearly. If you try to match your glass with the curve on the back of the bowl (certainly more of a challenge) then you can see more accurately what's going on inside of the carb while the engine is running.


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Brian Carlson
Carlson Racing Engines
Vector Cutz
www.CarlsonMotorsports.com
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765-339-4407
bcarlson@CarlsonMotorsports.com
 

flattop1

Dawg 89
Good Point Brian .
The Fuel is a fluid and there fore will be level at rest . same as tilting a glass of water .
Never considered the shaking aspect .
Would be interesting too see where it was in the middle of a high speed turn.
Centrifugal Force has to be acting on it .
 

Jimbo

If you talk the talk you should walk the walk
I cut both sides out of a float bowl and replaced them with clear poly-carbonate. What i determined is that the fuel shakes around so much you can't really see a fuel level.
However, the float level does make a difference in performance depending on a variety of things.
Track smooth or rough, "G" forces, what slide is being used, gas or methanol etc.
 

Jimbo

If you talk the talk you should walk the walk
You could also take the black hose off the drain and replace it with a clear one and get a reading.
 
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