Hutmacher, Greg wrote:
> Okay, I've learned my lesson...if it ain't broke, don't fix it. I made the
> mistake of trying to fine tune my Strombergs last night on my 76 TR6 even
> though they were running pretty well. I suspected my fuel/air mixture being
> a little off. Anyway, I tried out my new Colortune for the first time and
> now have totally screwed up the carb adjustment. I used the special
> adjusting tool with the hex key and the barrel that fits into the top of the
> dashpot. I got frustrated because no matter which way or how much I turned
> the adjustment tool, the Colortune never showed any changes (medium blue
> with occasional bright orange flashes). I made the mistake of continuing to
> turn the adjustment tool trying to get a deeper blue color on both carbs. I
> screwed something up because the color never changed but now the car runs
> much worse. The car idles rough where it was smooth before, when I
> accelerate hard, it seems to not have as much power and sounds "deeper". I
> also did the test where you lift the carb piston up and the idle dropped
> drastically (tried to stall). One thing I wondered is if I may have torn the
> rubber diaphram on my rear carb in trying to turn the needle because it was
> really hard to turn (as opposed to the front carb which turned fairly
> easily). This weekend, I'll take the dash pot covers off and check the
> diaphram and whatever else I can see. Any ideas? Also, what weight of oil is
> best for the dashpots? By the way, the guy at TSI told me that the
> Strombergs have almost no adjustment in the fuel air mixture. He said no
> matter how much you turn the adjustment, there is almost no change in the
> fuel air mixture on Strombergs since they are "tamper proof". This seems to
> be supported by what I saw on my Colortune. Thoughts?
> Thanks, Greg Hutmacher (bummed out because my formerly smooth running six is
> now running like crap)
Greg,
I agree that using a colortune is part black magic, but with time you get used
to how
to read it and it actually works quite well. I can think of a few points you
might
want to check. First, on your carbs there should be a grub screw that locks the
needle in the air valve. This must be loosened by removing the air valve
before you
can make any adjustments as it makes the "special tool" hard to turn if the
screw is
tight against the needle. (BTW if you can't seem to keep your carbs in tune,
chances
are that this screw is loose and vibration is moving the needle ever so
slightly.
After tuning, you must remove the top cover, lift out the air valve and lock
the grub
screw back down tight.)
Second, if you are missing the grub screw and you turn too far counterclockwise
you
will disengage the needle from the adjusting screw and you won't be able to get
the
mixture to change. Again, remove the air valve and correct. In fact, you may
want to
turn the tool and watch the needle while the air valve is out to see how many
turns
you have total, then keep count from the full up (or clockwise) position how
many
turns counterclockwise you are leaning the car out.
Finally, I find that the process of sticking the tool down in the dashpot
messes up
the mixture because of the vertical forces you inadvertently apply to the air
valve.
After you make an adjustment, rev the engine up to about 2500 rpm for a few
seconds to
clear it out and then let it settle back to an idle before looking at the
colortune
again.
Good luck!
Regards,
Brian Schlorff '61 TR-4 '64 TR-4 '72 TR-6 '79 Spit
---------------------------------------------------------------------
Power British Check out Power British
371 E. Main St. on the 'net!
Norristown, PA 19401
(610) 270-0505 http://www.powerbritish.com/~britcars
---------------------------------------------------------------------
|