John, when I rebuilt the carbs I replaced the o-rings and star washers in
both carbs. It took a lot of soaking with penetrating oil, but I got them
free. The needle was moving within the piston before I replaced the star
washer. What I'm not sure of is did I bend the needle when I was trying to
get the pieces apart. That's why I'm thinking about trying the piston from
my other carb. Now that you mention it, my needle is recessed into the
piston and not flush when the threads engage. This is probably my problem.
With the needle recessed, I can't 'lean' the carb enough to get the right
adjustment. I am going to use the new diaphragm from the existing piston on
the piston from my spare carb, then give that a try.
Thanks,
Ken
-----Original Message-----
From: John Jacobsen-Watts [mailto:johnw@wrq.com]
Sent: Thursday, April 27, 2000 1:24 PM
To: 'Ken Waringa'; 'Triumph Digest List'
Subject: RE: ZenithStromberg adj. needle carb and adjusting screw causes
problem.
Ken:
Hope you don't mind if I open this to the list.
I like the 20/50 idea, because the polymers theoretically will keep a
constant viscosity despite temp. A question: When you rebuilt the carbs, did
you pull the needle adjusters and put in fresh o rings and star washers? It
can be done...
You bring up an excellent point about the adjuster: It can freeze in place!!
That's why mine was shot: the Triumph tool could not move the adjuster as
crud over the years had cemented it AGAINST THE STAR WASHER! Another good
point you bring up: If your star washer is gone, is the adjuster really,
REALLY all the way down in the piston rod? If not, then no amount of turning
will ever get the needle-relation-to-jet back within spec. Test this by
pulling the air valve and pushing on the brass section of the needle while
feeling/looking for movement down the piston rod tube at the adjuster. Any
movement means these items are floating in the piston rod, because the
sideloaded screw into the slot on the needle does not "pin" the needle down,
only locate the assembly in relation to needle bias.
Another interesting twist is the fact that the piston rod in which the
needle adjuster and star washer reside, is an interference fit. This means
that it can be proud of, or recessed into, the air valve itself. You might
check to see if this is the case as it ought to be flush with the air valve
body proper. I wonder if you could "cheat" a non-responsive carb by moving
the piston rod in relation to the air valve.
John
-----Original Message-----
From: Ken Waringa [mailto:kwaringa@dynsys.com]
Sent: Thursday, April 27, 2000 10:57 AM
To: John Jacobsen-Watts
Subject: RE: ZenithStromberg adj. needle carb and adjusting screw causes
problem.
John, I've tried everything from Marvel Mystery oil to 20W-50 in the carbs,
I'm totally at a loss. The front carb had the star washer missing and the
needle adjuster was frozen when I bought the car. I've put kits in both
carbs. The back 3 plugs look great, but the front 3 are pretty black. I
was going to try the different air valve and needle to see if that helps.
Thanks for the info.
Ken
|