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MG MGA - Two items

1) When I was climbing a hill the car backfired, I believe through the carbs. Is that indicative of a fuel starvation issue?

2) As the car gets particularly hot the idle become what I would suggest to be "gallopy": bdddddupt, bdddddupt, buddddupt.

I've been told that a gallopy idle is a sign of a rich mixture. I get that the idle could lean out when hot, but why on earth would it get rich?

Thanks very much,

Tysen
T McCarthy

1) Not really. Not unless the car also shuddered and lost power.
2) Hmmm....

Go for a 10 mile run on the highway, pull over, and pull your #1 and #4 plug. If it's black, the car's running rich and you'll be able to tell which carb is richer/leaner than the other.

If you're backfiring and idling poorly, I would start with the timing. Where is it set now?
Mark

Whoops. What am I thinking? Yes, a lean mixture will cause backfire. I need more sleep.....
Mark J Michalak

If your carbs are heating excessivly the fuel in the float bowls expands resulting in raw fuel boiling into the carb throat. This will richen it up at idle as at speed the engine is drawing more fuel and movement of the car will help cool the float bowls.
Timing, vacuum leaks in the intake or carbs, and lean mixture all can contribute to backfire in the intake. exhaust back fires are usually caused by air leaks in the exahust system.
John H

The idle thing does sound like a rich mixture. The backfire thing is probably something else, not advancing correctly?
Tom

This thread was discussed between 14/06/2007 and 16/06/2007

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