Um, I've fully rebuilt the ZS emission carbs on my GT6+, and the only
way I could get the idle down was by blanking off those bypass
valves...
Can you explain why blanking the bypass valves helps the high idle
problem, and also suggest what the *real* problem might be? Blanking
the valves works great for me, but it seems to be a "work-around" and I
would much prefer to solve the root problem!
--- Atwell Haines <carbuff@nac.net> wrote:
>
> John,
>
> You may be the 'victim' of multiple problems.
>
> Now that the choke is out of the picture, it sounds
> as if the
> bypass/deceleration valve is bad. That's a common
> cause of a 2000 to 2500
> RPM fast idle.
>
> Got any gasket material left over? Blank that b/d
> valve off and see if
> your idle returns to normal...
>
> BTW if you are looking at the Bentley manual, be
> advised that the pic of
> the idle speed screw is misleading. The
> spring-biased 'idle' screw is for
> the _choke's_ fast idle; the actual idle screw is
> the slotted headless
> screw just forward of the other one. It has a 3/8
> locknut surrounding it.
> (This drove me bonkers for a while last year during
> my 'learning' phase.)
> Back that off before you muck with the bypass valve.
>
> You won't mess anything up by covering all the choke
> holes with your
> blanking gasket. And no, I don't know why they want
> the throttle propped
> open, unless its to make removing the choke's
> linkages easier.
>
> Atwell Haines
> '79 Spitfire, converted to manual choke, no beer
> cans used at all.
> Succasunna, NJ USA
>
> "When everything's coming your way, you're in the
> wrong lane, going the
> wrong way."
>
>
>
> At 04:53 PM 6/15/99 -0700, John Weale wrote:
> >
> > In my quest for a smog certificate, I blanked off
> the water
> >controlled choke in my Spit (using some gasket
> material, though I was
> >sorely tempted to use a bit of beer can just for
> the heck 'uv it). Now
> >the idle is around 2400 rather than the 1100 it
> started at. I adjusted it
> >down via the throttle speed screw, but am concerned
> that I screwed
> >something up. When removing the water choke, I did
> not hold the throttle
> >plate open as the manual (dug out after I did it of
> course) instructs.
> >Any idea why it says to do this? Is it reasonable
> to hope that the choke
> >was stuck open and blanking it off simply fixed the
> mixture (it did fail
> >smog due to high CO and HC's perhaps this
> contributed?)(hey, I can dream
> >:), raising the RPM's? Is blanking off all the
> holes between the carb and
> >water choke OK (I assume so, but that's gotten me
> into trouble before)?
> >
> >Thanks for any advice!
> >
> >John Weale
>
>
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