mgs
[Top] [All Lists]

Re: Help again! SU H2 carburetors running too rich

To: rdonahue@holli.com (Robert J. Donahue), british-cars@autox.net
Subject: Re: Help again! SU H2 carburetors running too rich
From: ambrose@cts.com (David Ambrose)
Date: Mon, 17 Jul 95 19:37 PDT
At 08:35 PM 7/17/95 EST, Robert J. Donahue wrote:
>First, thanks for the advice on the leaking gas. Thightening the jet gland nuts
>stopped both carbs from leaking. By the way, does centering the jets drive 
>anybody else crazy?
>
    There's a little aluminium plug in the SU tool kit which should help 
with that chore.

>Now I am trying to tune them. I can't seem to get the mixture right. Even
>with the jet adjusting nuts all the way up, the mixture is too rich. The 
>exhaust is black, the plugs are fouling and the Colortune plug glows
>yellow. The needle is ES which is supposed to be right for the H2s in the TD.
>The carbs were just rebuilt with the MOSS rebuild kit. I have the air 
>cleaner off, so it can't be an air restriction. I would think any air leaks 
>would only make the mixture leaner. The carb pistons move freely. Everything 
>is stock
>TD as far as I know.
>
>I am stumped again. Any ideas?
>
    You didn't mention the float level.  Have you checked it?  There is a 
spec for the clearance between the float and the fuel bowl lid.  This seems 
to be an approximation of the correct level, at best.  I've had a couple of 
carb sets where this was too high a fuel level.

    Remove the pistons, then turn on the ignition (I'm assimng an electric 
fuel pump crank if mechanical).  The gas level should be ~1/16" below the 
top of the jets.  If not,  adjust the bendy arm on the float or shim the 
needle valve as appropriate.


----
David Ambrose,  Proxima Corporation     ambrose@prxm.com
Play it cool,  play it cool,  50-50 fire and ice.


<Prev in Thread] Current Thread [Next in Thread>