I'm happy and relieved for you Mark, as the long-time owner of a '69 X Flow I was particularly concerned
as to the root cause of the vexing problem. Not knowing the exact causation is very infuriating, I suggest
you attempt a different start/warm-up technique in future, not letting the engine run at idle for an excessively long
warm up period. Not aware of your ambient temperature at the time the problem manifested itself, but 10 minutes
would not be necessary or advisable. Best to warm up it up by driving off after only a few
minutes, (2-3 at most) with light throttle inputs warming gradually under light load and moderate revs.
I reside in a region that experiences brutal winter conditions and B1800 is never exposed to them because
it remains safely and warmly ensconced in her heated garage/shop abode throughout the winter.
My daily drivers are required to operate in Arctically cold temps. cold Without oil or coolant heaters
there are days here when you can't realistically expect reliable startups from your vehicle, but even under these
conditions the wisdom is to engage in only minimally lengthy periods of static idle. Allowing the vehicle to warm-
up while driving under light load is best, contributes to cleaner engine internals and reduced wear and tear in the long term.
Please keep us posted of further developments and/or further conclusive findings regarding the problem.
Cheers cheers


Bert & B1800
"Tis well enough to know how much to know; and when to know, not to know, too much."