The distributor is open to the crancase-vent-wise. Condensation in the
engine can end up in the cap. Are your valve covers milky inside? Check
the underside of the oil fill cap or breather tube.
JR

Charles T. Low wrote:
Just to increase the odds that I'm not missing anything: I have condensation
inside my distributor cap. (This on a Chrysler 318, 1978,
www.ctlow.ca/Trojan26). Needless to say, it runs poorly that way! The seal
is old and brittle, and I have a new, marine cap on its way. We dried it out
the other day (after which it ran well), and I'm trying to leave the engine
hatch a tad open to improve ventilation (having put weather-stripping and
sound-insulation under it over the past few years...), and today it's wet
again. My bilges are always wet, long story, but they are.

I found an article on Car Talk
(http://www.cartalk.com/content/colum...ctober/06.html) about this.

Strangely, last year the engine began to run very rough, but only under very
specific conditions, those being all of i/ high heat, ii/ very calm days,
iii/ slow speed operation (e.g. 1400 rpm, ~7 kt), and iv) 20-30 minutes
underway. (If any of the conditions were absent, it didn't seem to happen.)
Then, if I opened the throttle, I would get very lacklustre performance for
a few minutes, then brief surges of normal operation, lasting less than a
second at first, but becoming more frequent and longer-lasting over a few
more minutes until the engine ran normally again. Of course, whenever I
brought my mechanic down to check it out, it ran normally.

This year, it is just rough, atmospheric conditions regardless. Apart from
being one year older, I also neglected to leave the engine hatch slightly
open over the winter lay-up.

I changed the plugs, and the leads, last year without solution. Plus, if it
were the leads, then why only intermittently?

The fuel pump was just tested and develops good pressure (and if faulty,
wouldn't behave intermittently this way?). I've checked the inline and
water-separating fuel filters, and they are clean. I have had the carburetor
rebuilt (and they said it was actually in pretty good shape anyway), and
then re-adjusted the idle jets. The air filter is clean.

Lots of people have scratched their heads over this. We didn't notice the
distributor cap condensation, though, until this year, and I'm hoping that's
it. But, from Car Talk, perhaps I should get a ventilated one, if such
exists...

Am I missing something obvious?

Thanks to all in advance.

Charles

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Charles T. Low
www.boatdocking.com

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