Jeff,
It's pretty rare to take a set of webers out of the box and get them
to work perfectly.
There are 2 routes you can take to initially set up webers if you have
never done so before.
One way is to read a pile of books, pull your webers apart, understand
how they work, get a range of setings from other people with similar
spec engines, buy the chokes/mains/ idles/ air correctors etc you
think, fit and test.
Then troubleshoot according to symptoms, buy more different sized
mains/ idles/ airs etc. 6 of each are required. And keep going by
trial and error.
The other way is to find a guy with a dyno and exhaust gas analyser,
who knows webers. He can set them up, test accurately, change mains
airs etc until it's right, then he'll charge you for his time, dyno
time and the mains/ airs etc he ended up leaving in your car when you
drove away (he won't charge you for the ones he tried and which didn't
work)
When you consider one set of 6 airs, or 6 mains etc costs around $120-
$150 per set; and you might go up a size on mains, then up one more
size; then down a size on airs, then change pumps... Etc etc trying to
get it right... You can very easily end up with $1,000 worth of idles/
mains/ airs etc sitting on your garage bench at home and a car that
still doesn't idle, or fluffs around 3,000 rpm on transition from
idles to mains....
The beauty of webers is they are almost infinitley adjustable. You can
e.g. richen by changing airs, or by changing mains etc. But the
problem with anything that gives you that many options is you need to
know what you are doing, and to be able to measure the effect of the
changes.
An su has a needle. That's pretty much it. And one SU feeds 2 or 3
cylinders There are around 6 things you can usually change on a
weber. At one choke per cylinder (ie x6) you can see trial and error
can become expensive at home...
Chris
www.myaustinhealey.com
Sent from my iPhone
On 01/09/2010, at 8:05 AM, "Jeff Pelletier" <jeff@pellfam.com> wrote:
> I know it's a jag question but "their all the same!!" Ive having
> troble
> with a triple weber conversion on a 69 jag.... Im about 30 degress
> advanced.. which I think is quite a bit??.. but it the best place it
> seems to run with the webers... I was told they like advance... but I
> didn't know that much??.. anyway.... the carbs have a slight
> (annoying) cough just as you slowly put your foot down... I believe
> its
> coming out of 2 of the 3 carbs... I cant shake it... any ideas....??
> idle is OK not great.. little shake... but when u step on it.... LIFE
> IS GOOD.... plenty of power and the sound is almost as good as a
> Healey!!...
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