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Re: Lumpy idle

To: <>,
Subject: Re: Lumpy idle
From: "Joe Short" <>
Date: Sat, 16 Mar 2002 13:42:11 -0500
You said the vacuum advance does not work correct?
Fix that first and then move on, it may be the problem.

----- Original Message -----<BR>
From: Rocky Frisco <><BR>
Date: Sat, 16 Mar 2002 00:05:35 -0600<BR>
To: "MG List <>MG List <>MG List 
<>MG List <>MG List" 
Subject: Re: Lumpy idle<BR>
> Jeff Sharpe wrote:<BR>
> > <BR>
> > Hi list,<BR>
> > <BR>
> > Trying to track down a lumpy low idle on my '71 B that has eluded me for 
> > long time.  Seems like it would be a vacuum leak, but not sure.  All ports 
> > the intake are plugged currently (found the vac advance was shot today, so 
> > disconnected it and plugged that port).  I'm wondering about the 
> > emission plumbing, and if it could be a factor.  Air Pump and Run-On valve 
> > gone.  A 'Y' line from the carbs and a line from the fuel tank evap are 
> > connected to the top of the charcoal canister.  The large port on the 
> > of the canister has a plug in it.  The valve cover breather is not 
> > to anything.  I tried connecting the valve cover port to the top of the<BR>
> > canister, and unplugging the lower port - no change.  I'm probably way 
> > track, but I've been through the carbs, timing etc over and over.  A clue 
> > be that it runs rich, even if I lean out the mixture all the way (air 
> > off).  By the way, carbs are orig HS4's, AUD 465, reshafted about five 
> > ago (and slightly leaky), new needles/seats/floats.  Looked at the 
> > today and they are both marked AAL.  What am I missing?<BR>
> <BR>
> Hope this isn't useless (long stretch): lift gently up and down on<BR>
> the carb setup. Not hard enough to damage even a dodgy connection,<BR>
> just a sort of gentle test of the gasket and manifold nuts. More<BR>
> often than you might expect, it makes the idle speed go up and down<BR>
> noticeably. This indicates an intake air leak.<BR>
> <BR>
> It's proverbial in Minis, where radical situations can cause the<BR>
> carb(s) to hit the rear bulkhead, but I have seen it caused on an<BR>
> MGA when a #$%$#$ "mechanic" leaned his elbow on the front carb hard<BR>
> enough to compress the manifold gasket. Results: two burnt valves,<BR>
> one ruined seat, one holed piston. I assume the same would be<BR>
> possible on a B.<BR>
> <BR>
> -Rock<BR>
> -- <BR>
> Red Dirt Rangers (Rocky on piano):<BR>
> JJ Cale Live (w/Rocky):<BR>
> The Luggage Fan Club:<BR>
> <BR>
> ///<BR>

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