QuestionI have a 79 MGB which I just put on the road after being storied 17 years.I re-did the fuel tank, gas lines, fuel pump and a friend did the Zenith carb.
The engine does not run well, so I replace the disc. cap, wires and spark plugs.
The timing and compression are OK.
The engine back fires thru the carb and does not accelerate very easily.
Could the choke be on all the time?
Pressing the accelerator seems to choke out the engine.
AnswerHi Jack,
A back fire out the carb can be a lot of things but the most common is a lean condition not a rich condition associated with a choke on all the time.
The Stromberg carb on the 75 and up MGBs had a odd symptom that the car just about would not run with the air filter off because BLM was trying to meet emission standards by leaning the mixture out so far that the fuel could not be drawn out of the jet properly without the added choking action (vacuum) created by the air filter itself.
To test if this is the problem (a lean condition) remove the air filter canister and with your hand partially restrict the air available to the carb intake. If you can improve the idle or acceleration performance by restricting some of the air going in, it proves that a lean condition is mostly your problem.
Also be sure you have enough oil in the top of the carb as that oil takes the place of an acceleration pump on a domestic carb. I use engine oil. Also most Strombergs have a jet adjustment down in the top of the carb with a 3mm Allen wrench. (Clock wise rich, counter clockwise leans)
Howard
