Amy Troutman says:
> My TR6 seems to be running lean
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.
> 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.
> 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.
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.
Good luck!
Kevin Riggs
'72 TR6
rkriggs@ingr.com
Huntsville, AL
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