Dick:
Thanks for the data. This confirms that my jets are installed correctly.
I am continuing to focus on the fact that pushing the air valves down
when the car is idling seemingly corrects the problem. Somebody (Don Malling?
You?) thought that the idea of weak springs was unlikely, given the low
spring coefficient of the springs in the first place.
My springs measured 5-5/8", very close to yours. One lister reported
6-1/16" for brand new, uninstalled springs. I have since stretched mine to
6", but I ordered new ones anyway.
Last night, I decided to replace my carb diaphragms, thinking that
perhaps they might contribute to the overall spring tension applied to
the air valve. I had a set that I had ordered months ago, but never put in
after I inspected the originals and decided that they were in good shape.
Well, I compared the old and the new last night, and the difference
is shocking. The old ones are much thinner and have almost no elasticity
compared to the new. The old ones are more like a vinyl covered thin cloth,
while my new ones are 3-4 times as thick, and infinitely more elastic.
I am not certain if the old ones are incorrect, or merely tired
(kinda like me). I am convinced that the new ones will apply a great deal
more downward force to the air valve as it rises. I will find out whether
this is the ticket tonight when I button up the engine and try to start it.
Wish me luck.
Thanks bunches for your help (and all the other listers).
Vance
-----Original Message-----
From: Sally or Dick Taylor [mailto:tr6taylor@webtv.net]
Sent: Thursday, August 14, 2003 8:05 PM
To: Navarrette, Vance
Subject: RE: Rough idle hints needed REDUX
Vance---Your jet and bushing height are close enough to where you should
be able to se the needle height with enough "richness" to satisfy the
engine.
I mention that my unmolested jets are set to the distance from the
bridge at .125 for a reference point. From the bridge to the bushing
around the jet, .105.
Since it is sometimes necessary to set the needle heights all the way up
to full-rich to get a decent idle, any lowering of the jet from where
you find yours would be like raising the needle: i.e. more richness.
While I was measuring the jet heights, I also measured the spring rate
on these carbs. On my balance scales, with counteracting weights from
1/4 oz up to one lb., the air valve springs came in at 4 oz. at the
height they operate when compressed at rest. While these springs are
also original (old), they seem to work fine when in the carb. They also
measure 5-3/4" free length.
Don't know what else I can pass one to you, partner, but I'm sure you'll
find the answer..
Dick
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