I'll have to second this, from my own experience. I converted a Triumph TR7
to HS6 carbs from the stock Zenith Strombergs. I had the backfire and poor
acceleration. I was sure it was in the HS6 carbs because I didn't have the
backfire with the ZS carbs (I had other problems like erratic high idling).
In my case, the problem was in the floats - the float to lid clearance was
a good 1/4 inch rather than the recommended setting of 1/8". Once I removed
the spacers from the valve seats to raise the float, the problem went away.
Now no backfire. So check fuel delivery, level of fuel in the float bowl,
and fuel mixture settings.
David Councill
67 BGT
72 B (restoration)
At 07:30 AM 5/7/2001 -0700, Lawrie Alexander wrote:
>A major vacuum leak on the intake side, fuel starvation or carbs set much
>too lean seem the most likely causes.
>
>Lawrie
>British Sportscar Center
>
>-----Original Message-----
>From: RETWIZBANG@aol.com <RETWIZBANG@aol.com>
>To: mgs@autox.team.net <mgs@autox.team.net>
>Date: Monday, May 07, 2001 6:41 AM
>Subject: Troubleshooting 69 MGB
>
> >I'm sure there is more, but although I have made modest gains through all
> >this, I still cannot get this thing to run strong. My symptoms remain:
> > 1) Timing remains at 13 degrees no matter the rpm (vacuum to
> >distributor diaphragm is drawn from the intake manifold, and is more strong
> >at idle - diminishes when rpms are increased)
> > 2) Fierce backfire through both carbs
> > 3) Very, very poor acceleration and low power
> >
> >I have considered the following for my next moves (purchases).
> > 1) New exhaust system (needs it anyway)
> > 2) New (or rebuilt distributor)
> >
> >Does anybody out there have a clue for me? I vowed to get the B running
> >correctly before I started dismantling for restoration, but I can't get to
> >first base. HELP!!!
> >
> >Rich Townsend
///
/// mgs@autox.team.net mailing list
/// (If they are dupes, this trailer may also catch them.)
|