David, et al,
Thanks for your responses. I haven't gotten to David's suggestions about
checking float bowls, but the pistons do move freely and the jets are
seating properly. As several have asked: Yes, I have been adjusting the
opening on the Unisync. Now when I put the Unisync on the back carb the idle
stays about the same and the ball on the UniSync rises to about midway in
the glass tube-where it's supposed to be. But when I attempt to put the
UniSync on the front carb the idle rises very rapidly to 3-4000 RPM (it
seems I read somewhere that this means the carb is too lean). I've loosend
the linkage between the chokes and tried to enrichen the front carb by 4 or
5 flats and it still causes the idle to go way up when the Unisync is
applied.
What next?
Thanks,
Monte
----- Original Message -----
From: "David Councill" <dcouncil@imt.net>
To: "MonteMorris" <mmorris@nemr.net>; "MG list" <mgs@autox.team.net>
Sent: Monday, April 14, 2003 10:52 PM
Subject: Re: SU adjustment
> Monte,
>
> My initial impression would be a massive vacuum leak of some kind. Or
fuel
> shortage to one carb. Having to cover the air intake to keep the car
> running would increase the vacuum and the pulling of petrol so it sure
> sounds like some form of fuel starvation to me.
>
> No doubt some details are missing. Yes, the carbs both should have
> significant suction.
>
> Things to look for - first, I'd take the covers off both float bowls and
> verify the fuel levels on both. With the tops and floats out, they should
> be maybe 2/3 or 3/4 full roughly. Take both carb tops off and remove
> pistons - make sure both jets at the base are seated similarly. Also, fuel
> should be maybe visible slightly below the jet (otherwise its plugged), As
> mentioned before, pistons should move freely up and down, particularly
when
> the dampers are not in (with dampers and oil, they are a bit more sluggish
> in response).
>
> many people have told me how tough it is to synchronize the dual carbs.
Not
> so. Before I had fancy gizmos like the Unisys and the Gunsen tools, I just
> made sure they were both set the same. Nuts turned down 12 flats to start,
> set the idle screws identically until you have the car idling well. When
> you press the throttle, both pistons should rise in unison. Then go from
> there. Forget the unisys until you have the carbs running reasonable
well -
> it is mainly used to measure the vacuum so you can synchronize the idle
> between both carbs.
>
> At least thats how I see it.
>
> David Councill
> 67 BGT
> 72 B
>
>
> At 07:27 PM 4/14/2003 -0500, MonteMorris wrote:
> >The UniSync covers only one carb at a time.
> >Being totally unfamiliar with carburation, I'm not sure how much suction
the
> >carbs should be creating, but it seems to be substantial. The car is
idling
> >very slowly at the starting adjustment for the throttle of one full turn
in
> >after it touches, and I must manually handle the throttle to keep the car
> >running. When I switch the Unisync from the front to rear carb the car
> >wants to dies unless I quickly cover the air intake(?) part of the carb
and
> >then the idle speed comes back up.
> >Monte
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