Bud,
The pin you describe sounds like one on my carbs that sits above the
starter box rather than through it. It is imbedded in a channel in the
carb body itself. It is spring loaded and serves as a two-position stop
for the choke cam lever as you describe. Mine have no knurled knobs.
The instructions with the rebuild kit describes this pin as a temperature
adjustment mechanism and says that you should push it in and rotate it
90 degrees to set it for winter weather. But I can't tell from that
whether cold weather requires that the pin restrict lever movement or
allow full movement. I changed the setting to allow full movement, and
it was VERY hard to do it (maybe because I don't have the knurled knobs?).
I had to get a short length of flexible plastic tubing, hold the lever
back, insert the tubing over the end of the pin, and rotate the tube to
try to get the pin to rotate. I chose this setting because the DPO had
attached an extra (and pretty strong) spring to act as a throttle return
spring. I think he was trying to overcome the restricted movement of the
cam lever and this extra spring actually could force the pin past its
normal stop. When I took the spring off (it was actually attached to the
starter solenoid at the other end!) the car ran badly. Of course there
were lots of other things wrong like the diaphrams in the bypass valves
and the gaskets in temperature compensating valves.
Tim Gaines
1974 TR6
1980 Spitfire
>Question for the list:
>
>Speaking of the starter box/choke. I was wondering what the "stop" is for on
>the starter box cover/choke. It's hard to describe but it's a spring loaded
>(brass looking) pin with a knurled knob on one end and a slot for a
>screwdriver
>on the end of that knob. The pin goes through a hole in the starter box cover
>and sticks out. Where it sticks out there is a hole in the pin with a tiny
>split
>pin that fits into the hole and extends out each side of the pin. This split
>pin has two positions it sits in when the brass pin is pushed in on it's
>spring
>and rotated 90 degrees. The end of the brass pin acts as a "stop" for the
>choke
>cam lever and it can be set in two positions. The two positions function to
>"stop" the choke cam lever (in either a more choke or less choke mode)
>when the
>choke is pulled out to it's full-choke position. The difference in the two
>positions being only about 3/8 inch.
>
>I've seen pictures of them in the manuals, ZS (the cover), Haynes (p.65), but
>nobody ever puts a name to the pins. Bentley had one picture (p. 24
>Figure 63)
>with the pin numbered (5) and an arrow pointing to it, but then never
>refers to
>the number in the text.
>
>Now if you can figure out what I'm talking about from that....can you tell me
>why there are two different stop positions for the choke when it's in the
>full-choke position? In other words....why is the choke stop adjustable? It
>also appears that only the back carbs have this adjustable choke stop
>while the
>front carbs have a non-adjustable choke stop.
>
>Thanks
>Bud
>71TR6 CC57365
>71TR6 CC65446
>
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