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Re: TR4 SU carbs

To: Bob <rlmcneit@cpis.net>
Subject: Re: TR4 SU carbs
From: Justin Wagner <jmwagner@greenheart.com>
Date: Wed, 18 Mar 1998 19:03:39 -0800
Cc: Triumph News Group <triumphs@Autox.Team.Net>
Organization: J.M.Wagner Sales, Ltd.
References: <35107EC8.15D5@cpis.net>
Bob wrote:
> 
> Hello everyone,
> I had my car sitting for a few months while I was gathering parts for my
> o\d transmission rebuild.  I got everything together, but I'm suddenly
> idling around 1200rpms.  I used to idle around 700-800.  I went to
> resync the carbs, which for some reason have always been very rich
> regardless whether I adjust the mixture nut up or down, but I couldn't
> get the car to idle under 1000rpms without getting rough and dying.  My
> timing seems alright.  What's the deal??
>                                 Bob Mc
> Once syncronized it drives great...just idles high


First suspect:  vacuum leak.

Check your throttle shafts.  Have the bushings/shafts worn?  If you
spray carb cleaner on them... and the car starts to die... (as if you
had sprayed the stuff directly into the carburretor)  then you've
probably got a good leak there.

If you have the TR 4A closed system...  temporarily plug the manifold
hose... and vent the valve cover to the atmosphere... and then check the
carbs... if this solves the problem... then you know you have to find a
leak in the hosing or repair/replace the fancy pvc valve.

Also check the hose/connection to the vacuum advance on the distributor,
etc.


Second Suspect: Wrong needle installed.  It may simply be outside of the
range of required adjustment.  Check to see if it's the right needle.



Third Suspect:  Butterflies are not adjusted correctly... or, otherwise,
are not closing properly for some reason...  study how they work...  and
see if there's some adjustment that needs to be made.



In regards to Butterflies... I have found a number of Triumphs with the
butterflies adjusted in such a way, that, even at full throttle, they
are not fully open...  after a 5 minute adjustment.. the owner (of many
years) is blown away by how fast his car is!!! 
Food for thought.


Without being there next to you...  and since I have to make assumptions
about your abilities... these are simply the first things that come to
mind.

--Justin
jmwagner@greenheart.com

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