Michael---Yes indeed, there are at least the three styles of ZS carbs
out there on the TR-six. As to which ones you have, check this:
The ones with adjustable jets can be raised or lowered (leaned or
richened) by moving the jet that's under a protective cap on the bottom.
The ones that have adjustable needles l(ike the '76 TR should have), can
be determined by inserting a long (7 inch) 1/8" Allen wrench down into
the damping tube. If you feel the wrench "catch", you have this style.
(The reason for having the tool you are purchasing)
Some carbs have neither adjustment, so owners are left with keeping the
engine in good shape, or....?...going to the later, adjustable needle
style.
More to the point, your front carb is probably set rich. Or the float
level is way too high. Plug fouling comes easy when engines must be set
rich for the (street driven) performance cams. You should be able to
prolong the drive time before having to clean or replace the plugs by
leaning out the carb that shows the sooty plugs. Also, go with the
hotter plugs that are more forgiving of the rich condition, Ths would be
the Champion N12...'s or the even hotter N14...'s, if you can still get
them. It's OK to just change these front three.
High energy ignitions help a lot!
Dick
From: SamuelsMA@aol.com
Listers:
With your help, I would like to revisit my driveability problems on my
'76. The car has high compression, cams, and headers. It tends to foul
the plugs very quickly, especially #s 1-3. Then it misfires, until I
clean or replace the plugs.
The carbs are Zenith-Stromberg CD2 models. I have both the Haynes repair
manual and the Haynes carburetor manual. The latter is a little
confusing, as it lists a myriad of Z-S models, but not mine. However,
the middle Z-S section shows a carburetor similar to mine with a white
damper cap and no adjustable jet assembly at the bottom.
I synchronized the carbs using the rubber hose method and the idle
screws. It now idles about 900 rpm and the hiss is similar at both
carbs.
The book refers to Z-S models similar to mine with adjustable jets,
adjustable needles, or neither. Which applies to my model? Also, most of
the text refers to adjusting the mixture by inserting a special tool
into the air valve, locking the base, and turning an allen key in one
direction or the other. I have ordered that tool from TRF. Does that
procedure apply to a CD2?
Finally, I am confused about whether my mixture is off. The plugs soot
up very rapidly, but I did the procedure with lifting the air valve and
letting it fall back down. In both cases, this led to a slight decrease
in revs, then a resumption of normal running. That isn't the response I
expected with an over-rich mixture. But the plugs seem to be the most
reliable sign. Also, the exhaust pipe ends look sooty to me. The
dashpots are both full.
I'm trying to do my part by reading the manuals carefully and following
procedures before leaning on you guys, but this is my first carbureted
car since the '70s and I could sure use a little sage advice.
Thanks.
Michael
'76 Tahiti blue
CF 57044U
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