[ROVERNET - UK] Mixture problems

Nathan Obuch nathanobuch at yahoo.com
Sun Oct 14 19:27:52 BST 2007

    I don't know that I can claim to be a Rover 'guru'
but off the top of my head, I think you are dealing
with an unrelated issue... i.e. any properly
functioning ignition system should not require any
changes in the fuel mixture/carb needles/etc. A
particularly strong spark can sometimes compensate a
bit for a lean misfire, but is just masking the
mixture  issue. 

   I would advise checking for any vacuum leaks you
might have introduced during the installation of the
Pertronix ignition. Check the float levels in the
carbs. Did the car run OK prior to installation of the
     Are all the rest of the components in the
ignition system up to snuff? Sometimes a higher
voltage output from a 'hot' coil can  break down weak
plug wires/cap/rotor. I would also advise checking the
strength of the spark just to be sure that you are
getting a good spark and don't have a defective new

Those are my thoughts-- I'm sure some real Rover gurus
will weigh in with their ideas!



--- Steven Dibdin <sdibdin at hotmail.com> wrote:

> Hi Rover Gurus,
> I've recently fitted a petronix ignition system to
> my '68 2000 TC along with 
> their 'flamethrower' coil (god awful name by the
> way). Timing is spot on, I 
> had to replace the old worn out advance weight
> springs as they were weak 
> with age. I have checked the advance curve with a
> strobe light and tacho 
> against the specs for my engine (10:1 compression)
> and that is as it should.
> My problem is that the fuel mixture seems to be off
> now. If I set the carbs' 
> at idle using the workshop manual method of lifting
> the pins and getting the 
> idle to rise then fall it runs a little rough at
> idle, after a few minutes 
> of running the plugs get sooted up. Suggesting it's
> too rich at idle. On the 
> road however, it runs far better than before, better
> acceleration, more 
> responsive and a smoother delivery of power.
> If I adjust the mixture at idle using my colourtune
> the idle pretty smooth 
> but it is running too lean on the road, power's
> lacking until I pull out the 
> choke to enrich the mixture.
> So my questions are: Has anyone else found a similar
> problem after changing 
> over to Petronix? Did they go for different needle
> profiles to accommodate 
> the new system? Do I need to find a rolling road to
> tune with new needles 
> now?
> Anybody out there have any suggestions?
> Many thanks,
> Steven Dibdin 
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