Tim Gaines writes:
<<<<<<<<<<<< Original post >>>>>>>>>>>>>>>>>>>>>>>>>>>>>
Thanks to all who responded to my question last week about the starter
box gasket. Now here is another one for you Stromberg carb experts. I
am at the point of tuning and balancing the 175 CD2s on my 74 TR6. With
three different manuals spread out in front of me and the VTR carb tuning
instructions as well, I can't find any reference to the throttle
speed screws on mine.
There are three adjusting screws on each carb. Lowest down is the fast
idle screw which pushes against the choke cam lever when the manual
choke is activated. I know how this works. The uppermost screw is the
usual throttle stop screw with a lock nut. If there weren't another
spring loaded screw just below this one, I would be balancing the carbs
(with a Unisyn) by turning the throttle stop screws. The middle spring
loaded screw sits on a lever which pivots. The upward movement of the
lever is stopped by the lock nut throttle stop screw above it. Screwing
this middle screw down opens the throttle but also (through the lever
action) pushes in a spring loaded pin in the carb body, just above the
starter box.
What I have done is lock the two throttle stop screws so that there is
the same clearance between the lobes for both carbs. Then I did my
balancing by adjusting the spring loaded screws. Does this sound
right? Is there some standard setting for the throttle stop screws?
Once again, thanks for any help you can give.
Tim Gaines
1974 TR6
1980 Spitfire
<<<<<<<<<<<< End of Snip >>>>>>>>>>>>>>>>>>>>>
Tim,
The spring loaded pins in the carburettor body is part of the
anti-run-on system. The pin operates a valve for the float bowl
vent. When the throttle is open the pin opens a passage to vent
the float bowl through a port at the face of the carb at the air
filter. When the throttle is shut the pin closes this port and
the float bowl is vented through the charcoal canister.
It has been a while since I've tuned my TR6 carbs and I can't
remember exactly which screws to turn so I won't guess and
possibly mislead you. If you don't get an answer I will go
look and then advise you. It will probably be the week end
before that happens, though.
Dave Massey
57 TR3
71 TR6 (with later stle carbs)
80 TR8
|