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MG MGB Technical - Help! My B would not start this morning...

Hello All,
I have never had any real problems with my B until this morning. It was a bit cool here in Atlanta (50's) and it was under an open cover.

It turned over but would only occasionally catch (try to start). After about 5 minutes of fiddling with the choke, etc, it started and ran fine all the way to work.

Now, this afternoon, same thing again, but it was much warmer (70's). It never would start this time, battery ran down, so I'm having it hauled home tonight.

I can't imagine what could have happened at such short notice. It seems to me that if it were points/condensor, it would not have ran OK after starting.

My choke mechanisn looks like it's working alright, no known issues.

Any ideas would be GREATLY appreciated.

Thanks in advance, David
David Steverson


As components wear or fatigue there is always that first time, often totally out of the blue, when they start to fail altogether. Did your engine crank normally when you first tried in the morning? In the afternoon? Or was it a bit slow to begin with? Did the car run completely normally once under way in the morning? Was the drive long enough to clear any fouling/flooding that may have occurred during starting, and to completely recharge battery?

Check electrical stuff first:
Battery connections clean and tight.
Battery ground cable clean and tight where it bolts to the body.
All connections to the starter solenoid clean and tight
All connections to coil clean and tight.
Points clean, gap checked.
Distributor cap checked for any cracks or carbon traces.
Plugs clean and gapped properly.
Spark plug and coil secondary wires clean and in good shape.

Any one of these things plus the coil itself, the battery, the starter, or even the alternator (if your battery is discharging faster than usual) could cause the problem as you've described it.

I can't think of too many carb-related things that could cause this - except bad gas or a bad fuel filter. Possibly a fuel pump FAILURE!

The more I think about it, I'd check the fuel pump first!

Good luck,

Allen Bachelder

Agreed. I would first check the fuel delivery system - pump and filter - then follow Allen's detailed steps regarding the ignition system. As Allen noted, checking the carbs should be last - this doesn't sound like a problem there.

Rick Stevens

Easiest first - clip a timing light onto the coil lead and each plug lead and watch the flashes as you crank. Flashing on coil lead but not plug lead points to rotor or cap breaking down, which can be more likely on cooler damper days. No flashing on coil lead then obviously check the voltages through the ignition primary circuit. Flashing on plug leads points to plugs, or fuel. If after cranking for a bit with no start remove a couple of plugs. If wet they are flooded, replace and crank with the choke pushed home and the throttle wide open, it should catch as it clears. No fuel smell means no fuel, could be pump or carbs. However unless you emptied the float chambers somehow after the previous run there should be enough left fuel in them to start the car and run for a few seconds at least even if the pump has failed. You should have a strong fuel smell but not wet. However if it seemed as if it were trying to catch but not making it, could be a weak battery or bad connections in the cranking circuit causing low ignition voltage, bad condenser, or insufficient mixture enrichment. For the condenser see how far a spark will jump from the coil lead to the block, should be at least 1/4", blue and emit a sharp crack. If it barely jumps a plug gap and is yellow it is the condenser.
Paul Hunt 2

Thank you all for the help. Turns out my points had slipped, I guess they did that a little at a time.

I'm having another issue now with my starter? I think I'll start a new thread.
David Steverson

This thread was discussed on 14/10/2006

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