v4 looper carb function

[reelbrothers]

my 140 carbs have the low speed needle, idle and mid orfices, I'm still trying to get my head around how the transition from idle to main jet works on these. I think if I understand how the carb works I can sleep a little better...some of you probably understand that!

 

[jakedaawg]

In general, as a throttle plate opens, different orifices are exposed to lower air pressures. As they experience this they turn from being an air bleed to being a fuel bleed allowing more fuel to be metered into the flow of air. The goal is to keep the fuel air mixture at 13.7 : 1 in a naturally aspirated engine. This is especially true of transition or "off-idle" circuits of carbs in general.

Now, I would guess that someone will come along and type "but, but, but..." and be perfectly correct. What I wrote is for carbs in general and not specific to any one loop charged engine or any other carb as you did not specify model. There exist many different designs of carbs and carb/throttle body systems.

 

[reelbrothers]

Thanks Jske, it seems established fact Loopers don't idle well, but while cleanin my cards I began trying to follow the fuel path which had me scratching my head how it transitions and changes the path, just one of those things I felt may help me to fine tune if I know how it does..