Subject: [JAGNUTS] Thanksgiving puzzle

From: Andrew <[email-masked]>
Date: Mon, 11 Oct 2004 12:43:21 -0600

I would appreciate your help in diagnosing the following problem. There could be prizes!

the 73 MGB GT ran fine one evening. The next day, it turned over fine, fired a few times but would not run. There is ample fuel, a coil swap made no difference, there is good spark on the coil wire going to the dizzy, but there does not seem to be a spark when grounding  any of the sparkplug lead ends. The points and condenser were replace a few months ago, and the points are properly gapped. When the ignition is on, there is only a slight spark/arc when manually opening/closing the points. I don't have a spare condenser, so I haven't test-swapped it.

any suggestions?

thanks
andrew

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From: "John Kutarna" <[email-masked]>
Date: Mon, 11 Oct 2004 13:13:09 -0600

Andrew:
Sounds like your points are grounding out - the post that holds the spring
arm of the movable point needs an insulating washer. Is it worn through or
maybe cracked? Failing this I'd look for carbon tracking on your coil, rotor
or distributor cap. Also it is possible that the adjustment on the points
has gone off and there is insufficient time for the coil to build up a
strong spark. By the way have you checked the oil level in the carb pots?
Good luck!
[email-masked]
----- Original Message -----
From: "Andrew" <[email-masked]>
To: "JAGNUT list" <[email-masked]>
Sent: Monday, October 11, 2004 12:43 PM
Subject: [JAGNUTS] Thanksgiving puzzle

> the 73 MGB GT ran fine one evening. The next day, it turned over fine,
fired a few times but would not run. There is ample fuel, a coil swap made
no difference, there is good spark on the coil wire going to the dizzy, but
there does not seem to be a spark when grounding  any of the sparkplug lead
ends. The points and condenser were replace a few months ago, and the points
are properly gapped. When the ignition is on, there is only a slight
spark/arc when manually opening/closing the points. I don't have a spare
condenser, so I haven't test-swapped it.
>
> any suggestions?
>
> thanks
> andrew
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From: "Bob" <[email-masked]>
Date: Mon, 11 Oct 2004 17:09:58 -0600

Another item could be a bad lead wire inside the distributor (i.e. the wire
inside the distributor).  I've had two bad ones on MG's this year.

Bob

-----Original Message-----
From: [email-masked] [mailto:[email-masked]] On
Behalf Of John Kutarna
Sent: October 11, 2004 1:13 PM
To: [email-masked]
Subject: Re: [JAGNUTS] Thanksgiving puzzle

Andrew:

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From: mike scales <[email-masked]>
Date: Mon, 11 Oct 2004 19:10:01 -0600

Hi Andrew;  Did you check the rotor? If you have good spark to the center
cap on the distributor, possibly the rotor, or the little carbon lead to the
rotor have failed. If you spray a quick shot of WD-40 inside the distributor
cap, it may effect a temporary cure.....Good luck...Mike.

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From: Grand Coulee <[email-masked]>
Date: Tue, 12 Oct 2004 15:53:25 -0600

I would check the rotor first ,then the condenser
if no cure make sure all the insulator washers are
on the points and in good condition.If no problem is
found on these items I would next check the cap ,then
the voltage at the coil (does it have an internal resistor).
If still no cure I would check the static timing and the fuel
delivery system.
Pip pip Tally Ho Jim

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From: Andrew <[email-masked]>
Date: Tue, 12 Oct 2004 17:34:43 -0600

Thanks to all for their suggestions. What a great group! Several mentioned
the rotor and although it didn't look too bad, a quick swap did in fact
correct the problem. The internal low tension lead was a good runner up -
mine looks like it might have been suspect.

Luigi, my MG does not have a "Brain on board". The only other occupant
onboard is a Prince (of Darkness). Thanks for your input.

Also, it was a good reminder to check the dash pot level - will have to do
that too,
Cheers,
Andrew