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
>For 10 months, I have been trying to get the bugs out of the subject
engine.
> I have
> 1) Cleaned and sealed the gas tank
> 2) Installed new fuel pump
> 3) Rebuilt and tuned SU HS4 carbs
> 4) Adjusted valves
> 5) Tightened the exhaust manifold to the exhaust pipes
> 6) Installed new vacuum advance diaphram unit on the 25D
distributor
> 7) Installed Pertronix ignition
> 8) Installed new rotor cap, plugs, and wires
> 9) Adjusted and tried the timing all over the clock (13 degrees
>BTDC?)
> 10) Checked compression at 145-150 across the board
> 11) Checked resistance of coil (3.5 ohms)
>
>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
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