Re: Idle (passive) jets

[William Kunz <satchel18@yahoo.com>]

Thanks Steven. All points well taken. The hunt is on
for that German-speaking, 50+ year old VW mechanic!

Bill Kunz
69 SQBK
NYC 
--- Steven Ayres <comwest@att.net> wrote:
> BillK=> Now where should I start
> => my adjustments with regard to
> => the idle (passive) jets, idle screw
> => and the idle air screw?
> 
> The pilot jets are not adjustable, just screw them
> in. They should have O
> rings on them.
> 
> Setting these carbs up properly requires a fine
> touch and a good deal of
> practice. Here's my standard recommendation on this:
> find a mechanic with
> relevant Porsche or high-performance VW experience
> and a lot of it. He'll be
> over 50 and expensive, and if he speaks German as
> his first language it's a
> plus. Pay him what it takes to get your carbs in
> tune, watch carefully and
> ask questions while he's doing it. Learn all you can
> about the process in
> general and your carbs in particular. If you study
> carefully you'll be able
> to keep them in tune from there, and it will be
> worth every penny. Without
> knowledgable help, this process can be extremely
> frustrating, particularly
> for beginners.
> 
> You know you *have* to study a good manual on this
> first, right? And you've
> got the tuneup procedures covered, of course --
> valves, dwell, timing,
> fuel -- plus careful inspection of your carbs to be
> sure that they're clean,
> they match down to the jets and they're the right
> ones for your car. Don't
> trust *any*thing -- any detail missed here will be
> at least a couple of days
> of frustration that nobody needs. You've also made
> sure there are no intake
> leaks (Butterflies need rebushing? Do it now or
> you're wasting your time)
> and your balance pipe is right.
> 
> From there the standard method -- not necessarily
> the best, but where most
> people start -- begins with setting the idle air
> screws at an arbitrary
> point. Some say a turn and a half, some say two,
> some say three or more.
> Odds are that the right adjustments will be
> different from that point and
> and different side-to-side, accounting for specific
> small variances in your
> carbs. You've set the idle screws and short linkages
> during the rebuild at
> an arbitrary and dead equal slightly-open point for
> the butterflies. If you
> didn't do that, you'll be working with six or eight
> variables rather than
> four in getting the idle right.
> 
> Start the motor, get it warmed up, take off the long
> linkage arms and work
> very gently with the idle air screws and carb
> balancer to find the optimum
> idle air rates. (Track every adjustment relative to
> the other carb so you
> don't get lost in the variables. The carbs are
> working more or less
> independently at this point, but they affect each
> other mechanically through
> the motor.) Then set the idle rpm and adjust your
> linkage arms to this.
> 
> Got a good idle now? Good start. Now you can work on
> accelerator pump
> adjustments and carb balance through the rpm range.
> Chokes are last,
> usually.
> 
> Other people will have other valid opinions and I
> may have got this wildly
> wrong -- it's been several years since I set up my
> carbs last and I don't
> mess with them when they're working right. I don't
> want to discourage anyone
> from working with their carbs, it's important to be
> hands-on here. I just
> want you to know it ain't simple and it doesn't
> happen fast, even for the
> experts.
> 
> Steven Ayres, Prescott AZ
> '66 Big Ghia
> 
>
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