[T3] Fuel Mixture

[Keith Park]

Well, I wouldn’t trust a sensor that shoved up the tailpipe... is it heated?
Go to the samba and read thru the D jet sticky...  you want to know exactly
how the pressure sensor works and understand it before you try and adjust it
or you will end up messing things up real bad, it’s a pretty complex little
mechanical gizmo but the idea is rather straight forward.

BASICALLY...  (I don’t have time to get into details tonight)
There are 3 adjustments, the inner stop, that you DON’T want to change, this
is the hardest to get right if you do, you want to pull apart the sensor and
epoxy it in place with some of the 5 minute stuff (will still be
removable)so that the inner stop wont move with the main mixture screw.  The
inner stop sets how lean you can go under high vacuum, if its not right you
can cause engine damage.

Main mixture screw, controls mixture over the whole range... is pretty
touchy.

Outer full load stop (that aluminum cap screw) which really isn’t a cap
screw at all but limits motion of the diaphragm and how rich you get at WOT.
This isn’t as touchy, but if its not right you can damage the irreplaceable
diaphragm too as it will try and extend out too far.

Getting the mixture right is critical for long engine life, good gas
mileage, and cool engine temperatures with aircooled engines.

Keith


Top Notch Restorations
topnotch at nycap.rr.com 
http://www.a383ina68.addr.com/radiorest/main.htm
71 Squareback "Hothe"
65 Notchback "El Baja Rojo"
65 Squareback "Eggcrate"
87 golf "Winterat"
93 RX7 "Redstur"

-----Original Message-----
From: type3-vwtype3.org-bounces at lists.vwtype3.org
[mailto:type3-vwtype3.org-bounces at lists.vwtype3.org] On Behalf Of Adriel
Rowley
Sent: Tuesday, March 15, 2011 2:12 AM
To: type3 at vwtype3.org
Subject: Re: [T3] Fuel Mixture




> From: topnotch at nycap.rr.com
> To: type3 at vwtype3.org
> Date: Mon, 14 Mar 2011 19:15:35 -0400
> Subject: Re: [T3] Fuel Mixture
> 
> 10.5 - 11.5 WOT, but it depends on where the sensor is mounted etc.  what
> matters is smooth acceleration.

I am using a borrowed exhaust gas analyzer so it is from the tailpipe.  
So I am right in my thinking that the mixture should become more rich.  As 
per what you stated on theSamba the inner stop needs to be turned in.  Have 
you since figured out how much of a turn affects the mixture?  What if I 
mess up the adjustment?

So long as the acceleration is smooth it can run lean?  I was told it would 
not allow good acceleration, so thus my questioning.  Also do not want to
ruin an just rebuilt engine, especially my first. ;)  Working on a second, 
but just a tear down and replace rings and anything else out of 
specification/worn/damaged.


Thank you,
Adriel
 		 	   		  
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