Thanks Kevin! Here are some additional comments and questions....
>Check for leaks in all vacuum lines--to distributor, to brake servo, from
>valve cover, from charcoal cannister. Also check carb mounting to manifold
>and from manifold to head. An air leak in any of these places can have a
>far more significant effect on mixture strength than adjustments you make at
>the needle. Your needle and seat shouldn't wear enough to cause significant
>poor adjustment, so (unless the car has been tampered with by you or a PO)
>there is almost certainly a vacuum leak elsewhere.
>
>If the carbs are warn, the throttle shaft might leak air or the bypass valve
>might be stuck open. These can cause poor idle, but don't typically cause
>the deposits you see on the plugs, though.
>
I bet you're right. Maybe it's sucking air through the brake-servo pipe - I
remember fighting with that when I took off the valve-cover. Perhaps I
didn't get it back on quite right. I'll try spraying some carb-cleaner in
that vicinity.
>> Turning the needle adjustment using the allen-wrench carb adjusting tool
>seems to
>> do nothing for me.
>
>Did you loosen the small screw that holds the needle in the bottom of the
>piston? You should loosen this screw before you try to make any
>adjustments. Turning the needle adjusting screw without first loosening
>this screw has probably chewed up the o-ring on the needle adjusting screw,
>and you may begin to leak oil out of the carb dashpots pretty quickly now.
> (I went through the identical process you seem to be going through, and my
>dashpots got so bad that they'd leak out all the oil in about 12 hours.)
> New o-rings come with a rebuild kit (about $15 each carb), but putting them
>in the first time is pretty tricky.
I have a question about that then. To back that setscrew out, you have to
take off the top-cover and pull the damper and diaphragm out. That isn't
mentioned in the manual. Could it be that small adjustments are OK, but
whirling it round and round, like I did, would damage the rings? They
shouldn't be too tough to replace with the right tool, should they?
>
>> Also, a question regarding the direction in which I should turn to richen
>> the mixture. I would have thought I should be unscrewing (turning
>> anti-clockwise) the needle, thereby increasing the gap between the jet and
>> the needle, allowing more fuel in. This seems contradictory to what
>> Bentley's says.
>
>The needle adjustment screw is reverse (left-hand) threaded.
Well, that explains that...
>
>If this doesn't clear up your problem, contact Scott Paisley
>(paisley@boulder.nist.gov) who can work out a fantastic trade of your broken
>adjustable carbs for a mint set of fixed-needle carbs. Scott's rates are
>very low, and he can probably make this exchange quite inexpensively.
>
Thanks, I'll bear that in mind. I hope it doesn't come to that though.
>Good luck!
>
Thanks!
>Kevin Riggs
>'72 TR6
>rkriggs@ingr.com
>Huntsville, AL
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