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Re: [TR] Spitfire SU Carbs

To: Randall <tr3driver@ca.rr.com>
Subject: Re: [TR] Spitfire SU Carbs
From: Roger Elliott <elliottr@rmi.net>
Date: Sun, 26 Nov 2006 17:13:13 -0600
I want to thank everyone who has offered advice on my problem.

Randall wrote:
>> I am at a loss of what else to try.  I don't think the mechanical fuel
>> pump can be over powering the floats. Can fuel be coming in around the
>> threads on the jets?
>>     
>
> Could be.  Have you checked that the sealing washers are in good shape ?
>   
I guess you mean there should be some at the base of the jet.  When I 
bought my lids (just recently) they came with the floats and jets 
installed.  There were no washers on the jets.  I looked at the diagram 
that I have from Joe Curto and could not find any washers mentioned.  Am 
I missing something? or perhaps this version of the SU doesn't use 
washers there?
>> I would appreciate any suggestions.
>>     
>
> I would remove the lid, put a 3/16" drill rod in place, hold the float against
> it, and blow into the fuel inlet.  It should take only very light finger
> pressure to get the valve to seal (or the weight of the float if you turn it
> upside down).  If you can blow air through it, then it will leak fuel.
>
> Also wouldn't hurt to put a fuel pressure gauge on temporarily.  Most vacuum
> test gauges will read the 2-4 psi of fuel pressure that SUs want; and you 
>should
> be able to pick one up for under $20.
>   
I haven't tried reinstalling the lids on the carbs yet.  But I slowly 
filled a jar with water as I was blowing through the fuel inlets.  The 
floats floated and cut off the air through the inlets before the water 
got to the seam on the plastic floats.  I was blowing the air with lung 
power so it probably doesn't match the fuel pump.

The float bowls seem pretty clean.

I guess I need to reinstall them on the car with a pressure gauge and 
see what happens.

Thanks you for your help Randall,

Roger Elliott


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