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Re: Runability Troubles

To: mikep@michindust.com
Subject: Re: Runability Troubles
From: Bob Sykes <stan.part@worldnet.att.net>
Date: Mon, 27 Mar 2000 21:22:30 -0800
mikep@michindust.com wrote:

> Good Day....I hope everyone enjoyed their cars this weekend!

Good Day, & yes indeed!
// 
> After installing my dual HS4 setup, syncing the carbs (UNISYN) and checking
> the mixture (COLORTUNE), the car runs great, except when in stop and go
> traffic or after an extended idle.  It "feels" like it is flooding itself,
//

Short answer, two words:  "Heat Shield"
(I'm assuming you don't have one)

Longer answer below:
I had the same problem when I initially fitted HS4s to one of my Spits.

> I installed Gross Jets in place of the float needles, but that does not
> appear to have made a difference.

BTDT - New needle valves, Grose Jets, didn't help, also checked &
rechecked floats, even set them "low". Also tried fuel pressure
regulator which helped some, but is unnecessary once the heatshield
is in place.
 
> Other potentially useful information:
> 1296, low miles
> Headers
//
This (the headers) is the other part of the equation:
The headers produce more radiant heat than the cast iron manifold.
When the car is moving at a reasonable clip, there is enough airflow
past the exhaust/carbs to keep them happy.  Not so for slow moving.

I can run the SUs with the stock manifold and no heatshield without
the problem you described.   I Can't run the headers sans heatshield,
even in the winter.  The ZS and Weber carbs do not seem to be as
susceptible to this malady.  Hope this helps...

-- 
LBC'ing U,
Bob (& Spitfires)
[digest mode]
http://home.att.net/~stan.part


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