Overheating / Steam or heat rising?

[rmbrown]

I'm learning.  I've researched and read much and realize that I probably just have an air bubble in the 50/50 that needs to be burped out but...

Wednesday night, after an incredibly long day of putting up a mast, prepping the boat, floating it and testing the new thru-hulls, plumbing the raw water intake with new thru-hull, strainer and hose, learning to bleed the fuel system since it wouldn't start, rebuilding the raw water pump (impeller fine but either worn plate or a bad seal when impeller was replaced) to get water pumping out the exhaust, my wife and I left about sunset for the 5 mile run upriver to our marina. 

When I throttled back down from 2500 approaching the railroad swing bridge in the dark, I heard the alarm.  I believe the gauge was reading about 190.  I recall where it was but not what the numbers say, so I'll verify tomorrow.  I shut it down, dropped a hook, and waited for it to cool down.  I opened up the engine compartment to accelerate the process and could see something... a little steam or simply head I can't say in hindsight... rising off the engine.

It cooled fine and I didn't run it beyond 2000 the rest of the trip in.

Question is whether whatever I saw rising indicates a problem that rings a bell with anyone?  I had a lot of engine work done while the boat was out in the yard because some smoke was rising from the compartment during the survey but that was blamed on the riser that's since been replaced.  I'll run it this weekend in the slip while I'm working on 1001 other things and see if I see anything but was just wondering if I'd smoked anything.  I'll check all fluid levels and colors before firing it up.

Any other advice?

[KWKloeber]

 Mike,

I'm sure you didn't smoke anything you didn't get hot enough to do any damage. But, without a better explanation how can we tell what you were looking at, you're not even sure. You see a stream? From where exactly? Can you pinpoint a general area or location?

How do you drain the coolant? It's probably just air that caused you to overheat or low coolant.  Did you remove the exhaust flange/replace a gasket?

Ken

[rmbrown]

Sorry... no stream... steam/smoke/heat rising...

Back with more data this weekend.

[KWKloeber]

 Mike,

Do you have a coolant overflow/reservoir tank? Or does the pressure overflow dump to the bilge?

When it cooled, were you able to check if you were low on coolant or just running hot?

[rmbrown]

Got a tank, under the head sink.  It was filled correctly when I left and raised as I'd expect while it was hot.  I checked it while the engine was shut down to cool.  I didn't check it after arriving in my marina.  It was after midnight by then and I'd just docked for the first time in a strange marina in a new boat in what turned out to be a flood stage river current and, having been at it since 6am, I was done!  Back tomorrow though and I'll definitely check levels. 

I don't believe it was coolant "steam" however... unless I have a leak somewhere.  I'll check each hose for drips and dribbles once I fire it up and I'll check each for that tell-tale white residue before firing it up.

:)

[Noah]

Hey Mike, don't forget to take some time to breathe and enjoy the fact that you've got a boat and it floats!

[rmbrown]

My wife and I discussed just that yesterday.  From this point forward, there will be mandatory chillaxing time.

[Ken Juul]

While you are checking for drips, make sure all the hose clamps are tight and the radiator cap is on tight.  Don't forget to make sure the heater lines are purged of air.  Lastly open the petcock or remove the bleed screw on the top of the thermostat housing, run the engine until you are getting your 50/50 mix out the petcock.  Then you will know you have all the air out.