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MG MGB Technical - Sudden Hesitation

I took my B out for a drive today, its absolutely beautiful in central OH, only to have a new problem arise.

Quick run down of the problem: when I go to accelerate the car misses badly, sounds like it wants to die, until about 2500-3000 RPM and then smoothes out again. After that when I am up to speed no more problem. When I got home I pulled the car in the garage and shut it down for about 5 minutes to visually check that nothing had worked its way loose; ie spark plug wires, wires to coil, etc. When I went to restart it and had to use the choke to get it to start?

The car is a '73 B with emissions removed and a pertronix kit. I haven't done anything recently except replace the rotor bottom a few weeks ago. I am wondering if it might be a clogged fuel filter??

Any advice will be appreciated as I am sure that it is something simple that I am missing. Thanks in advance.
Zach Dorsch

Zach. I am not sure what a "rotor bottom" is. It is possible, if the mixture is too rich, to carbon up the plugs which might cause the problem you describe. I had a similar problem when my daughter drove my 68 GT while I had to be out of town. It was cold and she had not become familiar with manual chokes yet. Carboned up plugs caused problems similar to what you describe. You may wish to replace the current plugs with a set of NGK BP6ES (or BP6RES) and see if the problem still exists. If not, check the mixture. You should have the HIF carb of which I have limited experience. Les
Les Bengtson

You may want to check the points if your car is so equipped. I too had the same problem and discovered the points had closed almost completely. After I reset them to .016" I just have an occasional stumble especially upon acceleration My second thought is now perhaps the condenser is a bad unit. I've had that happen on other cars. The distributor is new as are the points set. I would not be so quick to blame the carburetor.

Let us know how this problem evolves

Cheers

Gary
79 B
gary n.hansen

Zach

By "rotor bottom" do you mean the part that distributes the spark or the Pertronix part that contains the small magnets and slips over the 'square' part of the distributor shaft? There have been quite a few reports of poor quality new distributor rotors (holes inside the plastic moulding) such that they breakdown under certain driving conditions. SUggest you replace the rotor with another one if this is what you recently replaced.

Barry
73B (with Pertronix)
B.J. Quartermaine

Problem fixed!! Thanks again to all of the suggestions. The problem ended up being the oil in the carbs; there was very little oil in the carbs, so I topped them up and everything was fine.

Rotor "bottom" was a typo on my part, instead I meant rotor button.

Another point worth mentioning is that I am running Bosch platinum plugs (originally bought by mistake). Incidentally I could never get my B to run correctly with the NGK plugs, but with the Bosch plugs the car runs great.

Zach
Zach Dorsch

This thread was discussed between 02/09/2004 and 04/09/2004

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