When you say "cloak linkage", do you mean "choke linkage", or is this
something else?
--- "Patrick J. Horne" <horne@cs.utexas.edu> wrote:
> Before you adjust the carbs it is best to be sure that the rest of
> the
> engine is in good shape. Make sure the valves are adjusted correctly,
> the
> ignition (points, plugs and condenser and timing are correctly set
> (Points
> and condenser are not on your new distributor. Check the plug wires
> to be
> sure they are good.
>
> Once you know everything else is correct it is time to adjust the
> carbs.
>
> Remove the air filter and reach into the throats of the carbs and
> lift the
> pistons up as high as they will go. Let each one fall and listen for
> a
> "click" when it reaches the bottom. A "thud" or scraping sound, or
> the
> piston not dropping all the way means that you need to center the
> jet.
> This is a time consuming bit of trial and error until they are set
> correctly. I prefer to raise the jet as far as it will go to do this
> adjustment so the fattest part of the needle is as high as possible.
> Record the settings of the mixture so you can set them back where
> they
> were after you are finished. Loosten the nut above the mixture
> adjustment
> and lift/release the piston to see if it will drop all the way down.
> (the
> nut doesn't have to be really loose, just loose enough to allow the
> jet
> holder to move sideways a little. Tighten the nut and check again.
> Keep
> doing this until the carb "clicks". Reset the mixture and move to the
> other carb.
>
> The reason that you have very different readings with the unisyn is
> that
> the throttle butterflies in the two carbs are set differently.
> Disconnect
> the dumbell linkage from both carbs so that the throttle linkage is
> disconnected from both carbs. Make sure that the cloak linkage is not
> holding one of the carb jets down a bit. Start the car and adjust the
> idle
> speed adjusts (on the linkage for the butterflies) until the unisyn
> shows
> the same reading on both carbs. You may have to change the settings
> on
> both carbs until they are the same and idling at about 700~800 RPM.
> The
> readings need to be the same with the unisyn adjusted the same for
> each
> carb. By adjusting the unisyn you are changing the range of the
> unisyn.
> That should get the carbs in sync at idle.
>
> Next connect the throttle linkage on one carb. The unisyn should
> still
> show equal readings. Now adjust the dumbell for the other carb so
> that the
> length of the dumbell matches the location of the ball on the carb
> linkage. Just for fun check the balance again.
>
> Now it is time to set the idle mixture. There is a lift pin on the
> bottom of the carb, just below the throat, I believe on the side
> opposite the float bowl. Use this pin to lift the piston for a
> second or two. If the engine revs up a little, then slows down to a
> bit less than what it was running at idle, it is about right. Try
> the same with the other carb and go back and forth until they are
> the same. Adjust the nut around the jet on the bottom of each jet to
> make
> mixture admustments.
>
> Open up the setting on the unisyn and have someone rev the engine up
> to
> about 3000RPM. Check the balance again, it will probably be off by a
> bit.
> Adjust the dumbell until they match. (The idle balance will probably
> be
> off a bit, but not much.
>
> Go through the settings again and keep at it until it is running
> right.
>
> After spending the better part of a day going through all of this it
> is
> time to take a spin to see how your handwork did. Upon return treat
> youself to a beverage of you choice and relax!
>
> Peace,
> Pat
>
> - Support Habitat for Humanity, A "hand up", not a "hand out" -
>
> Pat Horne, Network Manager, Shop Supervisor, Future planner
> CS Dept, University of Texas, Austin, Tx. 78712 USA
> voice (512)471-9730, fax (512)471-8885, horne@cs.utexas.edu
>
> On Sat, 30 Mar 2002 WisslerJon@aol.com wrote:
>
> > Gary,
> >
> > You were absolutely correct. I was adjusting the damn air mixure
> screws and
> > not the idle screws. I finally figured out what the hell was going
> on.
> > Fortunately for me, a neighbor who restores old Mercedes stopped by
> and told
> > me I had to adjust the Unisyn to get a reading (as you said) and
> voila !!
> > Now the only problem is no matter what I do I can't get both carbs
> to get the
> > same reading. The rear carb, when covered by the Unisyn, causes
> the motor to
> > stumble a bit. I have the air mixture screw baily opened on that
> one. The
> > front carb barely gets a reading practically no matter what the
> heck I do. I
> > have it opened SEVERAL turns. Does this mean that my carbs are
> essentially
> > toast do you think? Despite the fact I probably have the SU's
> nowhere near
> > tuned, I went out for a test spin and WWWWWWWOOOOOOOOOWWWWWW !!!!!
> The car
> > absolutely hums !! No more stall at low RPM's, and if I punch the
> throttle
> > there is INSTANT response. Major improvement. Thanks again for
> such a fine
> > product, the excellent instructions, and the follow up advice. The
> wife and
> > I will heading out to dinner in the sunset tonight and I may be
> scaring the
> > hell out of here with my driving.
> >
> > 69 2000 (With the most excellent Gary Boone EI dizzy)
> > 69 510 Wagon L20B (With the dash removed waiting for a dash clock)
> > 69 Chev C10 4x4 307 2bl (HEI, Edlebrock manifold and carb waiting
> in the
> > garage)
> >
> > (I think I have too many things going at once !!!)
> > NOWROC
> > Troutdale, OR
> >
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=====
Thanks,
Adam Bradley
'70 Datsun 1600 Roadster SPL311-28181
'66 Datsun PL411 sedan PL411-022447
http://www.picturetrail.com/abend
Yahoo! Greetings - send holiday greetings for Easter, Passover
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