Backfiring through the carbs implies the valves open at the wrong time or
more likely a cylinder firing at the wrong time. The latter can be caused
by HT problems and sympathetic firing of a cylinder on intake with a
cylinder on compression. Condition of cap, rotor and leads? Plugs? Have
you looked at the HT system in the dark for any blue flashing? Do you still
have the electronic ignition? If so it could be that, rather than splashing
out on another electronic system it would be better to fit points and a
condenser - cheaper and easier to diagnose. If you have points have you
checked the dwell and timing? Is it correct and steady? Mixture is
unlikely to cause back-firing through the carbs although it can cause
mis-firing in the exhaust. Eliminate all ignition problems before looking
at carbs.
PaulH.
----- Original Message -----
From: "Don Vierling" <Don.Vierling@stago-us.com>
To: <DEVierling@aol.com>; <mgbnutt@aol.com>; <mgs@autox.team.net>
Sent: Tuesday, May 11, 2004 3:34 PM
Subject: backfiring
> Well, I finally have the car running again and re-timed, but now I
> still have an occasional backfiring problem (backfiring through the
> carburetor) combined with a hesitation upon acceleration in 2nd gear.
>
> Any suggestions where to start? I replaced the stock Zenith-Stromberg
> carb with one of those single SU HIF44 upgrades from Moss. Do I have
> the mixture set wrong? Do I need to change the needle? Perhaps this is
> still an ignition problem?
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