John -
The results of your tuning will be off if the throttle is open in any
way whatsoever at slow idle. Make sure the fast idle screws on both
carbs are not touching the throttle shaft arm when the car is sitting
at idle. The slow idle speed should only be determined by the slow
idle speed screw (the big one on top).
Also, when doing this test, your car should be idling steadily around
550 to 700 rpms... if it is any faster you will also get confusing
results.
The other thing you should check is to make sure the choke lever is
not sticking on... you may be adjusting it correctly, then when you
touch the choke and then put it down later the choke on the back carb
may be sticking in the on position. This is definitely pretty common
on BJ8s.
Hope that helps,
Alan
'53 BN1 '64 BJ8
On 6/2/06, John Rose <john@jesor.com> wrote:
> Good evening all,
>
> The HD8's on my 1966 BJ8 are driving me to distraction..
>
> After arriving at operating temperature, and balancing air flows with a
> Uni-Syn, I raised the pistons to the prescribed 1/32" and attained the
> desired slight increase in engine speed prior to it settling back...which
> conventional wisdom states that the correct mixture has been attained.
>
> However, when deploying a Colortune to ideally fine tune the SUs, my results
> were anything but consistent.
>
> The front cylinders have the desired blue color, but the back three are
> quite yellow...suggesting that the mixture is indeed as rich as it smells
> (with all garage doors open).
>
> Given the above, it appears that the rear unit does not have the correct
> mixture, despite the modest increase in engine speed mentioned above
> (reducing the jet screw setting causes it to stall when the piston is
> raised). In that the carbs were recently (less than 1,000 miles),
> rebuilt...by a professional...it would appear that "I" am doing something
> wrong.
>
> I look to the collective wisdom of the list to advise what where my errors
> might lie.
>
> Thank you for your thoughts.
>
> John
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