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Re: BN7--Intermittent miss, continued

To: Michael Oritt <Awgertoo@aol.com>
Subject: Re: BN7--Intermittent miss, continued
From: "M.E. & E.A. Driver" <edriver@sasktel.net>
Date: Tue, 20 Jul 2004 14:55:32 -0600
Hi Michael

In addition to my comments  last night I thought I could provide a
few more suggestions and ask a few questions.

First off the description you've provided is very general and it makes
it difficult to assess.  Questions that come to mind are does the
phenomenon you describe occur in ever gear through the entire rpm range
that you mention;  what happens when you lift off the gas pedal
is the problem still there, if so what form does it take.

Some potential areas which may give an intermittent miss are: minor
vacuum leak; vacuum leak in the vacuum advance until the centrifugal weights
take over; sticky centrifugal weights in the distributor; incorrectly gapped
plugs; worn distributor shaft and/or bearings which  constantly change the
dwell angle; a very fine crack in the distributor cap; and a dirty fuel filter.
In combination or  as separate items can give some of the symptoms you've
described.

  Have you checked the timing over the range of rpms given and noted any
changes?   Have you accelerated then slowed and then sped
up to find this phenomenon present, if this is the case, it's a fuel problem
caused by a dirty fuel filter.

I guess Michael until the description  is a bit more precise it may continue
to be a bit of a mystery.

Kind regards
Ed
Saskatoon, Saskatchewan
www.vintage-sportscar-touring.ca
'65 BJ8                '89 Morgan 4/4



Awgertoo@aol.com wrote:

> I posted a few weeks back about an intermittent miss on the 3000, to which I 
> received a number of helpful, if inconsistent, replies--some suggesting 
> mixture and others spark..  In the interim, the intermittency has become 
>"less 
> intermittent", appears pretty regularly when accelerating slowly or 
>moderately from 
> low RPM's (2000 or so) and seems to be more of a fluttering at constant 
> cruising speeds (3000 or so) but does NOT appear under load--there is no miss 
>under 
> hard acceleration all the way up to redline. 
> 
> Under the theory that most carburettor problems are spark-related I thought 
> that I would start with the ignition system.  In doing an "in-the-dark" test 
> for visible spark leaks tonight I happened to rest my forearm on both the 
> ignition cap and fender and got a definite shock which seems to be coming 
>from 
> around the coil lead where it comes out of the cap, though nothing was 
>visible.  I 
> could not find any crack or arc trail on the cap either in or out, but I 
> wonder if this is signifigant?
> 
> Best--Michael Oritt





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