Dear All,
Many thanks for all the helpful advice. I have now traced the twin
causes of the problem, and solved them. The causes were (a) loose
battery terminal connections and (b) inaccurate rev counter.
The rev counter is pretty accurate at higher revs, but below 1000 rpm it
can read as much as 100-150 rpm high. In other words, when I thought I
was ticking over at 850, I was ticking over at 700-750. Given the poor
connections at both battery terminals, the engine lost at least 250 revs
when the lights were switched on, leaving the poor car trying to run at
about 450 rpm. Altering the idle speed to a genuine 850 rpm, and
tightening the loose connections, has meant that the engine speed drops
by about 50 rpm when the lights are switched on, and there is no sign of
it stalling out. :-)
James, are you taking your idle speed from your rev counter, or from an
independent test machine? I can't get Carly to idle happily at 400 -
nor would I really expect to. Maybe your rev counter is reading a
little low?
ATB
--
Mike
Ellie - 1963 White Herald 1200 Convertible GA125624 CV
Connie - 1968 Conifer Herald 1200 Saloon GA237511 DL
Carly - 1977 Inca Yellow Spitfire 1500 FH105671
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