[C320-list] White Smoke and Overheating Diagnosis (A Lesson)

[Chris White]

 Hi Christian
Thanks for the story.I had a similar experience some years ago and have since fitted a scoop inlet strainer.These are available in brass or composite.Once the boat is out of the water you can easily fit these over the existing water inlet.
Regards
Chris WhiteC320 #449 'Dandy'Hythe Marina VillageUK

    On Tuesday, 1 June 2021, 15:28:20 BST, Christian <ccaper at gmail.com> wrote:  
 
 This list has taught me so much, other's stories have helped me, so I
thought I'd share an experience I had on Sunday, so others might learn.

I sail in Chicago, where we are on the hard for 7.5 months of the year.
Sunday, we launched, and launch day, though cathartic, is always a nerve
wracking shake down cruise for me of what's gonna go wrong now after being
on the hard.  My yard is on a river, about mile-ish off Lake Michigan.

Before leaving the yard dock, was idling engine for about an hour, checking
engine temp (fine), exhaust flow (seemed a hair low, but wasn't terribly
concerned, just a mental note).  After casting off, I had to wait for 2
bridges to be raised, requiring circling for about 45 mins with light load
on the engine.  After we passed the second bridge, now revving to higher
RPM (about 25) I checked exhaust again, and noticed some light white smoke
from exhaust, steady stream.  Started monitoring engine temp, and began
seeing the engine temp creep up slowly, going higher than normal (180), and
ticking up to about 190, still steady light white smoke.  We went on to our
harbor, able to raise sails soon.

Got to mooring safely.  Concerned I had coolant mixing with oil and was
burning coolant, once the engine cooled I checked oil color for milkiness.
Clean, and no oil burned.  Checked coolant level, same level.  Reading up
that night on white smoke, I read it's often steam or unburnt diesel.
Could be cooling problem, or could be a valve, timing, or injector pump
problem, crossed fingers it was cooling.  Since I wasn't blowing white
smoke on cold engine start, only when engine got hot, this was likely
steam, and an overheating problem.

Monday, I went back to the boat to dive into problem.  I'd replaced my
fresh water pump, thermostat, and mixing elbow 4 years ago, so eliminated
those as likely culprits.  I'd just replaced impeller, so knew that wasn't
a likely culprit either.  I took off the raw water strainer, clean.  With
the bowl off, I opened raw water thru hull to inspect flow, just a
trickle.  Interesting.  So I took the hose off the sea cock, opened thru
hull again, barely a trickle.  Felt into sea cock with pinky, felt squishy
stuff.  Flash light showed white plastic shopping back pieces.

Luckily I keep a coat hanger on board for random needs like this.  Bent an
end 90 degrees, went on a fishing expedition.  Over the next 2 hours, I
worked out a complete plastic shopping bag that had been sucked into, and
deepy jammed, in the valve on my seacock.  It was so jammed, at one point I
thought I would have to rebuild the seacock to free it, but eventually got
the entire bag out.  Most of the time I had to rock the seacock lever back
and forth to inch the bag through the valve. Now seacock flowed perfect.  I
think I picked up the plastic bag in the river, on our last Fall return to
yard, is my guess.

Hope this story helps others diagnose overheating problems, and the
importance of monitoring your exhaust, every sail.  This random mishap
could have become a costly repair if I wasn't closely monitoring my exhaust
and engine temp. And happy 2021 sailing season for us Great Lake sailors!

-Christian Caperton
1994 C320 #138 "Canuck" Monroe Harbor, Chicago, IL