You might want to check if the ignition timing changes a lot over the
800-1000 RPM range.
Some model Spits used a distributor advance curve that had a high rate
of advance over the 800-1200 RPM range. The idea was to give a
somewhat retarded timing condition at idle (for emissions), and to
get the correct amount of advance when the engine was turning faster
than idle RPMs.
The problem with this approach is that retarding the riming reduces the power
output,
which slows down the engine even more. Thus, the idle speed can be rather
sensitive to changes in the load.
Doug Braun
'72 Spit
At 09:24 AM 3/5/2003 +0000, Michael Hargreave Mawson wrote:
>I can accept that, but a 200 rpm drop just because the headlights are on
>seems excessive to me. Thanks for the reassurance that I am not alone,
>though!
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