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MG Car Repair/1966 MGB Runs for 20 miles or so.


QUESTION: My MGB started to buck and cough about 20 miles into my trip. Acted like a miss but would then would run smooth only to began to cough again.  This when on for about 10 minutes and then it started running fine.  I had turned around by then to try to limp home.  It started again about 20 miles later and did not recover.  I had to call AAA.  At home I sprayed starting fluid in the carbs and it ran fine on its' own.  What acts like that?  Thanks for your help.  Paul

ANSWER: Hi Paul,

Do this, if you have the car in quiet location. Turn on the ignition key to "ON" not "Start". Note that the small red light marked "ign" is lit up. And at the same time listen for clicking in the right rear of the car.

If the "ign" light is on but you didn't hear any clicking in the right rear of the car do this. Remove the battery cover behind the seats and behind the right hand battery you will see the electric fuel pump. With the key still in the "ON" position hit the fuel pump with a hammer handle or a piece of broom handle or a piece of wood. Hit the body of the pump not the black plastic cover end of the fuel pump. If it starts to click fast let it run and soon it will slow down to an occasional click. If it does that, then try to start the car. If it does all of that then have a MG specialist shop either replace the pump or clean and set the contacts in the pump. If all this is true and you want to repair the pump and have tools, let me know and I will tell you how to repair the pump.

If bumping it didn't make it start clicking then check for power to the pump with the key in the "ON" position first and if it has power check the grounding of the pump and if the ground is good replace the pump.

The spraying of starter fluid is a valid test of the fuel supply and the most common failure is the electric fuel pump under the car just behind the axle on the right side.

The other possible causes are, a crushed fuel line, a non vented gas cap or some thing in the fuel tank blocking the fuel pick up pipe.


---------- FOLLOW-UP ----------

QUESTION: Did what you suggested, I could hear the pump working.  I bought a solid state pump from Moss two years ago,(still looks new).  Could it be water in the tank?  Thanks, Paul

Yes Paul, that is another possible cause because the pump will pump water just like gasoline. The 66 MGB is easy to check. Just remove the screws in the cover over the float chamber and lift the top off of the float chamber being careful not to damage the float that is attached to that top. Any gasoline in the float chamber will be on top and any water will be on the bottom where the port to the jet is. If you have suction bulb, suck the contents of the float chamber and put in in a clear glass or jar then you can easily see if there is any water in the chamber. If you don't have any kind of suction bulb to suck the fuel out of the float chamber you can use a couple of shop rags. Then squeeze the contents into a clear glass or jar or into a large flat pan. Then you can clearly see if there is any water in the float chambers.

If you find the float chamber empty then you need to test the pump itself because some aftermarket pumps can make noise but not pump at all. Or any of the other possibles can apply that I gave you before.

Let me know,


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Howard M. Fitzcharles III


MG from 1956 (USA versions only) up and Engine theory.


Dealership line mechanic on MG, Triumph, Jaguar for 15 years, Instructor in commercial mechanics school 2 yr. Product information manager for piston and valve manufacture, Instructor & hotline answer man for import car parts importer 15 yrs.

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