datsun-roadsters
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Re: New (Rebuilt) SU's/idle speed

To: pielr@knick.net
Subject: Re: New (Rebuilt) SU's/idle speed
From: "John F Sandhoff" <sandhoff@compctr.ccs.csus.edu>
Date: Tue, 21 Dec 1999 09:53:51 PST8PDT
Nathan wrote:
> 1.  The car will not idle slower than 1500 RPM...
> 2.  Where are the vacuum lines supposed to be run?  Currently I have the
> intake vacuum port running to the vacuum advance (distributor).  The vacuum
> pod on the back of the front carb is capped.

If you've got the distributor vacuum advance plugged into a source
of manifold vacuum (15-20 in Hg), that's a major problem. You'll
find your timing WAY advanced, and advancing the timing speeds up
the engine. Try pulling the hose (plug the manifold tap with your finger),
and I suspect the speed will drop way back down.

Vacuum for the distributor needs to come off a port that is ZERO at
idle and INCREASES with opening the throttle - and that's what the little
fitting on the front carb (under the rear carb for a 1600) is for. I
suspect you're plugged into the smog 'burp valve' fitting right now.
Either that, or you're misconfigured with the overheat vacuum switch
that's part of the smog package (3-port vacuum switch on thermostat,
connects distributor, vacuum advance carb port, and manifold vacuum).

-- John
     John F Sandhoff   sandhoff@csus.edu   Sacramento, CA

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