That's right, George. The needle valve controls flow into the bowl,
but if the flow into the bowl is not properly limited (i.e. if the
float level is too high,) the excess fuel will flow out of the first
available hole -- the jet. If the needle valve is sticking open,
though, fuel will come out of the jet first, then every other hole it
can find because of the higher pressure.
And from the followup reply, it sure does sound like a very wrong
needle-jet combination has been installed. You might check that both
jets are the same size -- they only come in thtee sizes (0.090, 0.100
and 0.125 inch I.D.) One oversize jet would cause this kind of
problem. Top of the jet (you'll have to remove it from the carb) will
have no grooves (0.090,) one groove (0.100,) or two grooves (0.125)
cut into it. Also the needles should be the same. I believe they are
stamped with their identification letters just above the shoulder.
HTH,
Donald.
> From: "George P." <ygpz4re@hotmail.com>
> Date: Mon, 24 Mar 2003 09:53:32 -0500
>
> Doug wrote:
>
> "If the fuel is overflowing out of the jet, you obviously have a problem
> with the float or needle valve."
>
> I reply: I'm confused. I thought that the float/needle valve simply
> controlled fuel flow *into the bowl*, NOT into the jet. The jet is gravity
> fed and the needle (on the bottom of the piston) controls fuel flow from the
> jet into the venturi. Which part am I misunderstanding?
>
> And to the original lister who posted this problem: I think you hit the
> nail on the head when you guessed that the needle and/or jet were very wrong
> for your car. If you're turning it that far up and still running rich, the
> needle's gotta be wrong (not sure about the jet, that would depend on the
> carb, I guess). In case you're unaware, needles have specific profiles, the
> diameter of the needle is carefully measured over 12 or so points on the
> needle. The only way to "truly" get it right, is to run your engine with a
> meter hooked up to the exhaust. Other listers have done it and are far more
> knowledgeable than I am, so I hope they chime in with their techniques (I
> may be doing this soon also...) and experiences. For the short term, call
> Joe Curto (718-762-SUSU - 7878 or www.joecurto.com) and tell him what you've
> got (he'll ask lots of questions about the car, engine, mods, carbs, etc.)
> and he'll make a recommendation that's probably pretty close to spot on.
> About 12 bucks (plus shipping) later, you'll have the proper needles for
> your carbs.
>
> Good luck.
>
> George P.
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