Roland
I will assume you have an Autolite 2 barrel Carb. Your problem
does sound like it is at the power valve. Here are some possibilities.
Too Rich condition:
Too little air;
1. Check to make sure the choke is wide open.
Too much fuel;
2. Take the top of the carb off, and with just the fuel pump ON, check
the float level also check that the fuel shuts off.
3. Check the size of the main jets, your carb should have #'s 38 to 46
depending on the altitude of your location. Jet size in the parts
manual reduces by 2 for every 5,000 ft increase in altitude. Any jet
size over #50 is too big, in my opinion, for a 2 barrel carb. It is
always good to know the jet size anyway.
If your carb has a TAG number on it, that can be referenced to the jet size
for that carb.
4. Now for the power valve. The power valve will leak if it is not
seated correctly or if the gasket is poor. The power valve could also just
be bad. Check to see if there is a number on the power valve and
compare it to the number on the valve you removed. The numbers should be
the same or close, the number indicates at what vacuum the valve opens.
The power valve will leak if the vacuum to it is low. The power
valve is closed when the vacuum is high and opens when the vacuum is low.
Low vacuum can mean the internal vacuum passage is not open and needs to be
cleaned. Another possibility, you may have over tightened the screws for
the power valve cover and warped it enough to allow air in, and created a
continuous low vacuum condition. Take the cover off and check it for
flatness and cracks, also check the gasket for breaks and flaws.
Never over tighten the screws for the power valve cover or the
accelerator pump, those covers can and will bend or warp, snug is just fine
for those screws.
I hope this helps you, I'm betting your problem is in #4.
Here is a link to carb shop that maybe helpful.
http://www.cybervillage.com/ponycarburetor/index.htm
Ron Fraser
-----Original Message-----
From: "Flüeler Roland, FLO" [mailto:roland.flueeler@cantrade.ch]
Sent: Tuesday, May 25, 1999 8:44 AM
To: 'tigers@autox.team.net'
Subject: My carb - the "overrich" and unadjustable (II)
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