[Mgs] Ignition light glowing

[PaulHunt73]

The float valves sticking open can be to worn valves or dirty fuel.  As both 
do it the temptation is to blame the fuel (HS-equipped cars didn't have 
filters, HIF did), but then they both could be equally worn.  Remove the 
float chamber lids and see if there is any dirt in the bottom of the 
chambers.  If you replace the valves get the Viton-tipped ones and not Grose 
'jets'.

Given the warning light and the ammeter indication it's not charging. 
Remove the wires from the dynamo (I assume), connect the dynamo terminals 
together, and a voltmeter on its 20v scale between the connection and earth. 
Start the engine - don't rev it - and slooowly increase the revs.  The meter 
should show 20v by the time it reaches 1000rpm.

If it doesn't the dynamo is faulty.  If it only shows 0.5 to 1v the field 
winding may be faulty.  If it shows 4-5v the armature winding may be faulty, 
or it could be worn brushes.

If the dynamo is OK it must be connections or the control box.  Reconnect 
the wires to the control box and run the engine at about 1000rpm.  Measure 
the voltage on the F terminals at the dynamo and the control box, which 
should be the same, and the D terminals at the control box and the dynamo, 
which should also be the same.  Increasing the engine speed should close the 
cut-out relay (the one that is normally open) if it hasn't already.  Check 
the voltage is the same on both sides of the contact (which should be much 
the same as on the D terminal), if not clean the contact carefully with fine 
wet and dry.  If it hasn't operated check there is an earth on the E 
terminal of the control box.

For starters.

PaulH.


----- Original Message ----- 
From: "Bill Snyder" <wtsnyder at bellsouth.net>
To: <mgs at autox.team.net>
Sent: Friday, October 11, 2013 1:38 PM
Subject: [Mgs] Ignition light glowing


> Hello list. I have a 66 MGB that hasn't been driven much this year. Took 
> it
> out yesterday on a very nice Smoky Mountain day. I have two issues that
> require advice. The needle valves on both carb float bowls stick
> occasionally. Is there a proper way to clean or lubricate them to prevent
> sticking?
>
>
>
> Secondly, when I took her out this AM the ignition light remains at a
> constant glow while the engine is running and the ammeter (non-stock) is
> registering discharge (Minus 15V). I took a quick look for loose wires or
> connections, but nothing obvious. Where do I start to track down the 
> fault?
>
>
>
> Thanks in advance.
>
>
>
> Bill Snyder, Waynesville, NC
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