Mitch:
The fact that you need to have your choke on to get the car to
run means you have a massive vacuum leak somewhere. the mixture is too
lean at an idle, so you correct this by having the choke on.
Get your propane torch out (unlit of course) and start spraying
propane around the manifold, vacuum lines, etc until you find the leak.
If you cannot find a leak this way, start disconnecting hoses (brake
booster, emissions, etc) and plugging them. You will find that the idle
changes dramatically at some point (not just a little, but a very
distinct change). You will then need to address that leak. If your
carbon canister is connected, make sure you check the hoses going to it.
I found that I had a very large leak coming in through the main breather
hose. This is fairly common, as the carbon canister gets tried and
starts letting in too much air. Rebuilding the carbon canister will
correct this. If you are running a non-stock cam, you may need to put a
restrictor in the breather hose, as hot cams are a lot less tolerant of
controlled air leaks from the carbon canister.
No, the choke does not move the butterflies. Technically, it is
not a choke, but rather is an enrichment valve. It does not "choke" the
engine, rather it adds extra fuel, which is why your engine runs better
with it engaged.
The puddle of oil is most likely from the dashpots of your
carbs. It is common for them to start leaking after 30 years. Do you
need to top off your dashpots more than once every 6 months or so? If
yes, then they are leaking. Disassemble the top of the carb, and
withdraw the air valve. Adjust the needle to FULL LEAN (counter
clockwise on the needle adjustment tool). This will release the needle
from the adjuster. Loosen the needle set screw (on the side of the
valve) and pull on the needle with your fingers to remove it. If it
seems stuck, just be patient, it will come out. DO NOT BEND IT, DO NOT
use pliers or any other tool!!!! Then use a small screwdriver, and push
the needle adjuster assembly out through the top of the air valve. There
will be a small o-ring on the assembly that needs to be replaced. I got
my o-rings at the hardware store, and they worked just fine. Reassemble
and top off with fresh oil. Presto, no more leaks.
My o-rings were so old that they were square from 30 years of
being soaked in oil and pressure from the air valve.
Cheers,
Vance
-----Original Message-----
From: mitch vamos [mailto:mitchvamos@operamail.com]
Sent: Saturday, March 12, 2005 10:52 PM
To: Navarrette, Vance
Subject: any ideas?
i was reading nelsons article on your site.
trying to diagnoce my multiple carb problems.
#1 is my choke problem. only runs on full choke, give it less and dies
right away.
i took the carbs off tonight, checked the whole carb. a friend that owns
a shop told me the choke should open the butterfly. i operated both of
them on the desk here, the choke moves the butterfly about 1/16 inch but
really doesn't visibly open. i don't see how it could
.
also when looking into the intake manifold with the carbs off i noticed
a puddle of oil in each one, hmmm. i have a K&n like filter on the valve
cover vent , the only thing i could think of is it's too restrictive but
i could easily blow thru it so i doubt that. i also have those brass
fittings on the right side of each carb plugged off, no charcoal
cannister hooked up although i have one.
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