thermostat not opening..what happens to intake water?

skennelly

What happens to the intake water when the thermostat doesn't open?  Does it just bypass the engine and exit the exhaust?

Handymans342

If your engine is raw water cooled the flow will stop at the Tstat although it does allow a small amount to go thru. If your engine is fresh water cooled it will go thru the heat exchangers and out the exhaust

zaverin1

Yep
out via the exhaust

skennelly

I'm getting myself all worked up...yesterday started the boat and it was idling at the dock.  Temp guage was around 220 when I shut it down.  Was seeing a fair amount of white smoke from the exhaust...keep in mind temps were around 35 degree's out.

I've read white smoke is related to head gasket...please no.  I did check the oil and it was clean.

aero3113

@skennelly , at 35 degrees I think your going to get a lot of smoke(what looks like smoke) but it's really steam. Think of your car sitting in the driveway after you started it up from cold at this temperature. I think its just the hot exhaust hitting the cold air forming condensation. 

skennelly

Thanks for the reassurance @aero3113 I thought that too until reading around on the internet this morning and getting worked up .  I'm heading to it today to check into the usual suspects...impeller and thermostat.  Yard doesn't their water systems on yet so I can't run it on the trailer unfortunately.

aero3113

The internet will do that to you, good luck!!

Willhound

And sitting all winter that first start with last year's fuel and whatever stabilizer you used will smoke a bit too. Add the cold temps and it's running a little rich as well as condensation......probably fine. But check the things you mentioned and you'll feel better.

aero3113

Also, do you fog your engine before layup? When that oil burns off you'll get a lot of smoke too.

J3ff

skennelly said:

Thanks for the reassurance @aero3113 I thought that too until reading around on the internet this morning and getting worked up .  I'm heading to it today to check into the usual suspects...impeller and thermostat.  Yard doesn't their water systems on yet so I can't run it on the trailer unfortunately.

yes, under a certain temp you will get a lot of white "smoke" .. the difference is it doesn't smell bad. 

jhofmann

Still, 220 degrees at idle is way too hot, it your temprature gauge is accurate, and that woud explain the steam.

J3ff

This was out of the water right? Maybe something was wrong with your supply?

212rowboat

Stats, the majority of them, are designed to fail open, not closed... This isn't to say yours isn't simply jammed after sitting all winter.  
The biggest indicator of bad head gaskets is not only temperature, but wild fluctuation of temperatures.. 220 is spooky.  220 to 170 to 220 to 190 to 220 in a ten second window is more than spooky.  If you rev engine and it goes down in temperature, its time to look at your circ pumps impeller.. If it rises in temp when you rev, gaskets are most likely. 
The good news is neither are that bad to repair if you catch it in time.. Both can be done engine in boat an an afternoon.  
Sometimes, it's just the way it is in a raw water engine, if the engines water pump isn't fairly new or lubricated, they freeze.  Its easy to see bad pump on a car as it has that great silly clutch fan hanging off front and any wear in seal will be readily evident... On a boat its harder to spot.  
But more likely yet?  You simply aren't moving enough water at extended idle to cool the engine.  

skennelly

@J3ff - No this all happened in the lake after launch.


Here's what I found today

Handymans342

Yuck

skennelly

This impeller was 2.5 seasons old.

skennelly

@Alswagg - Maybe a dumb question...but where are the coolers location on a Mag 350?

J3ff

What kind of impeller was it? Will want to avoid that brand.. my current impeller is going to be at least 2 years old now.. maybe more, not sure when the previous owner swapped it out.  Off I go to google "bravo 3 impeller change"

Is there two pumps on a Closed loop system? 

skennelly

@J3ff - I replaced my entire pump assembly and it came with an impeller.  I'm pretty sure it was a OEM replacement pump.

aero3113

WoW, only 2.5 seasons. Looks like that would have been in use for 10 seasons! At least you found the issue now and not out on a trip. Anyway the engine was started with no water somehow?

aero3113

I wonder if the cold water made the impeller brittle?

skennelly

Engine was never run we without water

212rowboat

note to b3 pump owners:  at start of season, rotate pump by hand before letting the engine drive it... especially if it's in its second+ year.  doesn't even have to be a full revolution.  ...just enough to let them 'remember' the shape they're supposed to have instead of what the off season of relaxing and pressing into the drum and any imperfections has allowed.  when the first vane goes, the piece that broke off takes the one behind it out, and the next- snowball.    

skennelly

@Alswagg - 2002 mag 350 mpi / 270

skennelly

@Alswagg - Thanks

reneechris14

Collect all the pieces try to put the puzzle back together to see if got all of it.

Dream_Inn

Well, if you learn anything from this, it's really that you need to change impellers every two years.  & the very best thing you can do is to change them in the spring, BEFORE you start your boat for the first time.  Have you seen what that impeller looks like after sitting all winter?  The chances of it going the first start in the spring is very high!  definitely make sure you find the pieces from it, or it will cause headaches thru the summer.

davidbrooks

After having issues with my last boat struggling to prime the water system i also do a quick check to make sure that water is flowing when the engine first starts up.  Paranoid yes.  I can do this by squeezing the large soft water hose top front of each engine.  You can normally feel water flowing.  You can also loosen the hose clamp and pull it off for a min to make sure water is flowing.  Otherwise it is a wait and see game and by the point your temps go over 180 your impeller is toast.

skennelly

I hear you all.  I told my wife this is the first season I planned to launch before our storage yard had water turned on and I couldn't start the boat on muffs.  First time I've ever launched and started in one shot.  Lesson learned for sure.  Can't really flush out the bits and pieces of the impeller until I have hose water...so currently I'm at the yards mercy.

And still hoping there isn't any further damage from the high temps.

Dream_Inn

This is a huge reason why I like having vesselview.  It gives me water pressure status coming from the pump.  Being I keep my boat on the lift, it has to prime each weekend when I put it in (not a big issue, but just worth noting).  I watch it each time I start the engines, and yes, I'm a bit paranoid about it.  Heck, I've seen it drop while up on plane and pulled it off plane even before the alarm went off.  It was an engine hose that came off that time. 

& as far as loosen engine hose, I have something even simpler.  Just loosen the blue engine plug on the output and/or input of pump before you even start up.

thepriceisright

Is this something that's usually replaced with an outdrive and bellows service?