[Top] [All Lists]

Re: spark plug condition

To: William Killeffer <>,
Subject: Re: spark plug condition
From: Barney Gaylord <>
Date: Sun, 10 Nov 2002 01:55:04 -0600
At 06:47 PM 11/8/02 -0500, William Killeffer wrote:
>.... The three rear spark plugs were a dark gray, almost as if the engine 
>had been running rich but not severely. The front plug was white, which is 
>an indicator that the mixture is lean or the plug is too hot for the 
>engine. What would cause that and how can I fix it? ....

With the siamesed intake ports, the #2 and #3 cylinders will run just a tad 
richer that the #1 and #4 cylinders. and if the carbs are just a bit on the 
rich side you may notice ths as a slight difference in the coloring of the 
spark plugs.  Your combination of colored plugs may only indicate that the 
front carburetor is running a little more lean that the rear one.  Forced 
to a compromise, I personally prefer gray to white (but not black).

>.... As far as running rich goes, no matter what I do I can't find that 
>magic carburettor setting point between rich and lean. ....

When the carburetors are in tune and well matched, and you still can't find 
that happy medium where it will at least idle nice, it's time to check the 
ignition parts again, and also do a compression check.

Barney Gaylord
1958 MGA with an attitude

///  or try
///  Archives at

<Prev in Thread] Current Thread [Next in Thread>