I think I know my problem now. My Uni-syn doesn't create enough suction
to get the bubble to float. I tighten the adjuster on the Uni-syn all
the way down and the bubble still won't float. At this point the car is
on the verge of a stall and the bubble still isn't moving. The only way
I could get it to move was to bring the rev's up to around 2500 so the
other carb could pull enough fuel in to keep it from stalling. At this
point enough suction is created to bring the bubble up. This can't be
normal? Is my new Uni-syn bad or could I be leaking air in through a
manifold or something? There does seem to be a good amount of air being
sucked into the carbs though. My Uni-syn is made by Edelbrock, model "A"
unisyn multiple carburator synchronizer, 4025. Could I have gotten a
wrong model?
Thanks,
Matt Peterson, going to be an expert on SU carbs before I'm done :)
'68 1600
Zimmerman, MN
On Thu, 13 May 1999 15:38:51 -0400 "Andrew Jacobs"
<Legal-Z@worldnet.att.net> writes:
>matt,
>there should be an adjustment on your uni-syn that changes the size of
>the
>opening inside the black rubber ring. this allows the bubble to float
>at
>idle. i.e. the smaller (or is it bigger--i can't remember) the
>opening,
>the greater the amount of air that can flow through the tube, and
>hence the
>bubble floats. just adjust the opening back and forth until the
>bubble
>floats at the idle your car is set at now. as for the rest of the
>adjustment proceedure, you need to know what you're turning first.
>the big
>screws on the bottom that you turned to get your car to start are the
>mixture adjustments. counter clockwise when looking down is leaner,
>clockwise is richer. where they are now is probably a good point to
>start
>at. you need to check your plugs and see what color they are. if
>black go
>leaner and if white go richer. keep doing this (with a short drive at
>operating temperature in between) until the plugs are dry and brown.
>you
>need to check the #1 and #4 plug each time to make sure each carb is
>at the
>right mixture. once you get the mixture right, then worry about the
>balance
>and idle. you use the idle adjustment screws to balance the carbs.
>get the
>idle close to where you want it and then get out the uni-syn (and
>adjust it
>as above). then place it over each carb and see how close the bubble
>is to
>being in the same position on the uni-syn. don't freak because it can
>be
>WAY off. if the height of the bubbles is different, then you have to
>adjust
>each carb--turn the screw on the carb with the higher bubble so the
>idle on
>it is lower (counter-clockwise i think), and the screw on the carb
>with the
>bubble in the lower position clockwise to raise the setting on it.
>remember
>each time you make an adjustment to rev the motor a couple of times by
>hand
>so the engine runs at its true new setting. repeat these adjustments
>until
>the bubble is at the same height for each carb, then see where you
>want your
>idle. adjust up or down accordingly with equal turns on each carb and
>then
>check the bubbles to make sure they are still at the same height, and
>remember to rev the engine after each adjustment. once you've found
>the
>right idle speed, go for a drive and see what happens. when you
>return,
>check one more time with the uni-syn to make sure everything is still
>in
>sync.
>hope this helps,
>andy
>-----Original Message-----
>From: Matthew W Peterson <pete-3@juno.com>
>To: datsun-roadsters@autox.team.net <datsun-roadsters@autox.team.net>
>Date: Wednesday, May 12, 1999 11:32 PM
>Subject: finally she started
>
>
>>Hi everyone,
>>
>>I am pleased to report that my car is now running. I ended up
>turning in
>>the two round nuts on the bottom of the domed half of the carbs all
>the
>>way and then turning them out about 1.5 turns. She started after
>that
>>but it's running rough and very loud because of the new hole in my
>>muffler. Now I have to re-adjust the carbs to get them running in
>>unisyn. Last time I balanced the carbs this whole thing happened so
>>could I get some clarification on the process. First, when you put
>the
>>Uni-syn to the carb what do you adjust to get the thing to float? I
>>adjusted the little idle adjuster screw on the side of the carb last
>>time. I also couldn't get the thing in the Uni-syn to float while
>the
>>engine was idling so I ended up adjusting it while the engine was at
>2500
>>rpms. I am now thinking, should I have adjusted the round nuts on
>the
>>bottom of the carbs where the fuel line comes in instead of the idle
>>adjuster screws? Is this where I went wrong and therefore had to
>adjust
>>them at a higher rpm than idle?
>>
>>Just want to make sure that I do it right this time
>>
>>Thanks so much for all the replies
>>Matt Peterson
>>'68 1600
>>Zimmerman, Mn
>>
>>
>
>
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