> -----Original Message-----
> From: Hanna, Mark
> Sent: Tuesday, April 07, 1998 9:51 AM
> To: 'Shannon'
> Subject: RE: Need help with SU's
>
> Shannon,
> It sounds like the rear carb may not be closing its
> butterfly valve all the way. (this is a circular disk
> inside the carb body that rotates with the throttle
> shaft) Its possible it has slipped out of position and is not allowing
> the throttle to close all of the way.This
> may be why that even with the idle adj. screw backed out all the way
> and the throttle closed , it is
> still hissing louder than the front carb. Also you mention "extra
> springs all over the place" If my memory serves me it should only have
> three springs. Please do not use extra or stronger throttle
> return springs . You risk wearing out the throttle
> shaft bushing surface . If you do this the carb will leak air and
> upset the fuel air mixture . This is a common problem on old worn out
> SU's.
> Good Luck,
> Mark Hanna
> AN5L/13731
>
> -----Original Message-----
> From: Shannon [SMTP:squeedle@khoral.com]
> Sent: Tuesday, April 07, 1998 8:57 AM
> To: spridgets@autox.team.net
> Subject: Need help with SU's
>
> Here are my symptoms:
>
> 1) When I adjust the fuel mixture per Haynes manual's
> instruction, the
> back one is always too rich (as evidenced by carboned-up spark
> plugs).
>
> 2) both linkages (choke & throttle) do not return the way they
> should, in
> spite of extra springs all over the place.
>
> 3) Corollary to 2, when I synchronize the carbs, a) it's almost
> impossible
> to get the back one not to have a louder hiss, b) invariably
> when I
> retighten the throttle linkage, 2 things happen - the idle speed
> decreases
> and the carbs become de-synched (yes, the back one is louder).
> Then when
> I drive the thing, the idle speed goes back up to 2000RPM
>
> I'm afraid I've messed up the throttle linkage by pressing too
> hard on the
> bolts - the back one is hard to reach and tighten.
>
> Basically I'm not sure what to do about it. I futzed with it
> for 2 hours
> last night, & it seemed to be ok when I raised the throttle up,
> but then
> this morning it was back to idling at 2000RPM once I got on the
> road.
>
> I can tell where it sticks, too, although I don't know the name
> of the
> part(s). Between the back carb & the linkage bolt there is some
> sort of
> spacer and the 2-tine fork-shaped piece of metal, which links to
> the
> little linkage pin thingie, and which actually seems to open the
> throttle.
> If you press on this piece of metal firmly, the idle speed goes
> back down,
> but this is not where it naturally returns to.
>
> Unfortunately the throttle adjustment screw on the back carb is
> almost all
> the way out. So basically I'm not sure what to do now - rebuild
> the
> carb(s), get new linkage(s) or what?
>
> Addendum: when looking at it last night, I noticed that the
> front carb
> piston was stuck open. When I took it apart, I noticed that
> someone (NOT
> me) did not reinstall it correctly - the needle was just resting
> in the
> bottom, with the spacer sitting on top of it! This was not like
> this
> before I took it to a certain mechanic. Anyway, I put the
> needle back the
> way it was supposed to be. Could this have caused some of these
> problems?
> Would it still cause these problems?
>
> Sorry this is so long, but I wanted to give a full description
> so you kind
> folks could help me out better. :)
>
> Thanks,
> Shannon
>
> ======================================================================
> ========
> If I had a dime for every dime I had. . .
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