Re: [T3] cutoff valve

["Brad" <BnPWOOD2@att.net>]

Well,
    I checked the cutoff valves.  The original one has a number 5 on the
orifice.  The one I got from the shop has a number 55.

    I am starting to believe that this is not my "real" problem.  I swapped
the original from the left to the right carb.  I moved the new one to the
left.  The right hand pipe is still backfiring.  Both carbs have always
seemed a bit on the rich side (evidence is lots of black carbon on inside of
exhaust).  Can a carb related issue cause the backfiring?  I am no expert,
but my limited knowledge tells me that this is not as likely a carb issue.
    I found some other things that scare me a bit.  1.  I was pretty low on
oil.  I watch my pressure gage like crazy, and it is always reading good.
2. There are 2 "pipes" that are part of the 2 piece housing around the main
fan.  These were plugged so that all of the air was forced onto the
cylinders.  The right hand plug is gone from the housing.  This makes less
coiling air going across the cylinders?
    Is it possible that I have a valve sticking or burned that is causing
this problem?


----- Original Message -----
From: "Jim Adney" <jadney@vwtype3.org>
To: <type3@vwtype3.org>
Sent: Saturday, August 02, 2003 9:21 PM
Subject: Re: [T3] cutoff valve


> On 2 Aug 2003 at 12:08, Brad wrote:
>
> > I'm the guy with the type 3 engine in my dune buggy.  I have had a
coupkle
> > monthe s relatively problem free driving of my buggy.  However, I have a
new
> > problem.  I need some help.  FYI, it is a 1600 dual carb.
> >
> >     The thing was running great.  then, it started running lousy.  I
found
> > that the right hand intake manifold was loose where it bolts to the
head.  I
> > tightened that up, and it was running great.  At least for a few days.
> > Yesterday, the idle cutoff valve on the right hand carb must have just
> > dropped off while going down the road.  It suddenly started running
lousy on
> > my way home from work.  I had no power to speak of.  When I got home I
found
> > that the cutoff valve was missing.  I went to the local dune buggy shop,
all
> > they had was a used one that was close.  They gave it to me.  It now has
a
> > bit more power, but under load when I put the petal to the metal, it has
> > quite a bit of miss, and it starts popping in the right hand header.
>
> There are both 6V and 12V cutoff valves, and each comes in a couple
different
> orifice sizes. You know what voltage you need, so just unscrew the other
one
> and see what number is stamped down hear the nozzle of the one you have
left.
>
> The used one you got may not be opening. You can test it by just pulling
the
> wire off. If you do this with the ignition ON you should be able to hear
the
> solenoid click in. If you do this with the engine running you should be
able to
> hear the engine change speed dramatically.
>
> These cutoff valves amount to a large weight cantilevered way out from
their
> mounting threads. As such they put a lot of stress on those threads. When
the
> carb came loose that made the situation even worse. I believe it is
possible to
> even destroy the threads in the carb body where the cutoff valves screw
in. You
> need to be really careful that nothing here is allowed to come loose and
rattle
> around, because that's when the damage gets done. It might be worthwhile
to use
> a bit of mild LocTite on those threads once you're sure you have the right
part
> in there.
>
> It's also possible that something else came loose when the carb was
rattling
> around. You may have to pull the top off the carb and see if the float
valve
> and main jet are still tightly in place.
>
> >     I ASSume that the problem is the valve, as it is the only thing that
I
> > am aware of that changed between the time it was running well and now.
> >
> >     Where can I get the correct one?
>
> This is probably the best place to ask first.
>
> >     Do I possibly have another problem?
>
> Sure, the possibilities are almost unlimited, but it sounds like you're
> starting at the right place.
>
>
> --
> *******************************
> Jim Adney, jadney@vwtype3.org
> Madison, Wisconsin, USA
> *******************************
>
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