Overheating after first day launch

[jkru]

So I launched my 2006 Searay 260 with a ( 261 hours ) 350 MAG MPI Horizon after changing the drive oil and engine oil and running it at my RV storage. I have a one of those through hull with leg pickups for seawater cooling with a closed system as well. During running it on dry land I close of the through hull and just run the muffs at idle to get the oil up to temperature. This year I doubled the size of the oil filter to add some filtration but ended up overfilling by 1/4 a quart or so. While leaving the doc all of a sudden I started seeing the temperature go up, then the warning alarm and shut off the engine immediately, opened the hatch and coolant was everywhere and vapor billowing out of the engine compartment. Got towed back and and didn't bother starting it again.

Couple of points and questions:

The through hull shut off valve for cooling was turned on ( handle vertical with the hose ) so all cooling should have been working.

When the engine starts and the oil goes into the filter It actually takes up about a quart so not sure if the overfill is a problem or not.

Any ideas what it could be? I am thinking hose but don't know where to start looking in that situation.

Also bigger filter good idea or bad?

1/4 Quart over fill a problem?

Thanks! (Not a good first day for my boating season )

 

[HT32BSX115]

Re: Overheating after first day launch

So I launched my 2006 Searay 260 with a ( 261 hours ) 350 MAG MPI Horizon after changing the drive oil and engine oil and running it at my RV storage. I have a one of those through hull with leg pickups for seawater cooling with a closed system as well. During running it on dry land I close of the through hull and just run the muffs at idle to get the oil up to temperature. This year I doubled the size of the oil filter to add some filtration but ended up overfilling by 1/4 a quart or so. While leaving the doc all of a sudden I started seeing the temperature go up, then the warning alarm and shut off the engine immediately, opened the hatch and coolant was everywhere and vapor billowing out of the engine compartment. Got towed back and and didn't bother starting it again.

Couple of points and questions:

The through hull shut off valve for cooling was turned on ( handle vertical with the hose ) so all cooling should have been working.

When the engine starts and the oil goes into the filter It actually takes up about a quart so not sure if the overfill is a problem or not.

Any ideas what it could be? I am thinking hose but don't know where to start looking in that situation.

Also bigger filter good idea or bad?

1/4 Quart over fill a problem?

Thanks! (Not a good first day for my boating season )

Howdy,


I am not sure what you mean by

I have a one of those through hull with leg pickups for seawater cooling with a closed system as well.

Do you have thru-hull water pickup or do you have drive raw water pickup?

Also, when was your raw water pump replaced last?


1/4qt over full is insignificant and the size of the filter makes no difference other than it will take longer to fill unless you fill it before you install it.

Regards,


Rick

 

[FreeBeeTony]

Re: Overheating after first day launch

My guess is the raw water pump is belt drive and fed by the thru hull pick-up and you destroyed the impeller when you ran it on land w/ the thru hull pick-up blocked.

 

[HT32BSX115]

Re: Overheating after first day launch

Yeah. A 350 MAG MPI (300HP probably) in a boat that big should be a Bravo I or III

It shouldn't have a thru-hull water pick up though unless someone added one. If that was the case, It shouldn't be using the "leg/transom mount" hose then unless someone plumbed it that way. (I wouldn't)

I have closed cooling in my 21' FourWinns (454/Bravo III) and it works just fine with the drive raw water pickup. I've ran it in 85 degree water and the (t-stat regulated) temp doesn't change at all!

1. remove and inspect/replace your raw water pump.

2. ensure that you know how your raw water shut-off operates (if you have one) do you also have a sea-water strainer?

3. ANY time you run the engine on "muffs", ensure that the water is on before you start the engine and after you shut down before you turn it (the water) off....

 

[jkru]

Re: Overheating after first day launch

Thanks Everyone for their responses!!.. Just to clarify it is a 2006 MPI Horizon 350 Mag with a Bravo III. The engine has what I think is called a shower cooling system? It has a fresh water pickup from both the leg and via the through hull pickup. It also has a closed system through the heat ex-changer. For the first time since having this boat new I shut off the through hull and ran the muffs at idle to warm the oil up for the change as directed by SeaRay (Not sure if that had anything to do with it). Needless to say everything was fine until I left the doc (Murphy's law). There is coolant everywhere in the bildge I didn't even try to look to see if it was a hose on the close side of the system and just dropped it off at Lake Union SeaRay in Redmond. I will update you on what they say it is but my guess is a hose on the close side of the system went. Why? I have no idea except for two things.

1) I ran it with the through hull closed and the muffs attached only.
2) I used seafoam in the oil for the first time which bumped the temp up a little higher than normal while bringing the oil up to temp.

I am thinking I will probably pull the raw water pump and replace the impeller as you have suggested.

Thanks to everyone who replied. Ill update the thread once I hear back from SeaRay I am hoping its not the manifold etc..

 

[04fxdwgi]

Re: Overheating after first day launch

Thanks Everyone for their responses!!.. Just to clarify it is a 2006 MPI Horizon 350 Mag with a Bravo III. The engine has what I think is called a shower cooling system? It has a fresh water pickup from both the leg and via the through hull pickup. It also has a closed system through the heat ex-changer. For the first time since having this boat new I shut off the through hull and ran the muffs at idle to warm the oil up for the change as directed by SeaRay (Not sure if that had anything to do with it). Needless to say everything was fine until I left the doc (Murphy's law). There is coolant everywhere in the bildge I didn't even try to look to see if it was a hose on the close side of the system and just dropped it off at Lake Union SeaRay in Redmond. I will update you on what they say it is but my guess is a hose on the close side of the system went. Why? I have no idea except for two things.

1) I ran it with the through hull closed and the muffs attached only.
2) I used seafoam in the oil for the first time which bumped the temp up a little higher than normal while bringing the oil up to temp.

I am thinking I will probably pull the raw water pump and replace the impeller as you have suggested.

Thanks to everyone who replied. Ill update the thread once I hear back from SeaRay I am hoping its not the manifold etc..

Drive shower is usually not a factory item that I have seen. Some folks that install them re-plumb everything and use the drive pickup to supply the water for the shower only and then add an extra thru hull for the raw water pump. They normally don't connect the 2 pickups. (But, some high performance BBC Mercs did used to have 2 pickups some years ago) If yours is plumbed that way and you put the muffs on the lower leg to run on land, you "could have" been only feeding the drive shower and run the raw water pump dry with no water supplied to it, destroying the pump, and probably, the rubber exhaust couplers between the risers and pipes and the flappers too.

Yours may be different, with the 2 pickups are plumbed to a common manifold, though. Another possibility is that water going thru muffs via drive pickup and feeding the shower and raw water pump was of insufficient quanity to supply the pump, with all the water just going right back out thru the shower, again, starving and frying the raw water pump.

I installed a flush manifold in my engine compartment to flush without muffs. Close valve isolating line from pickup and open another, connecting garden hose to raw water pump supply line and idle like that all day long, if I want.

I doubt very much oil subject has anything to do with what you are seeing... This may be as simple as bad hose or you may have simply popped off a closed system hose because of a loose hose clamp, too.

 

[MarkSee]

Re: Overheating after first day launch

I am thinking I will probably pull the raw water pump and replace the impeller as you have suggested.

Seems like a good idea when you do that, trace back the hose going to the input side of the housing to find out if that leads to the thru hull only or is part of a 'Y' system also leading back to the transom for water pickup via the drive.

Mark

 

[scoflaw]

Re: Overheating after first day launch

I've got the same setup. Even though it is a Y system and you close the seacock, the pump won't pickup water from the drive. When I flush, I ductape the gills in the lower unit and use a toilet plunger style flusher on the thru hull

Bottom line.... You fried your impeller

 

[Bt Doctur]

Re: Overheating after first day launch

Except for the fact that Bravo`s dont have an inpeller in the lower unit,You cant have a Y because the engine driven pump would be sucking air on land.
Need to know exactly how your plumbing is.

 

[scoflaw]

Re: Overheating after first day launch

Oh, there is def a Y. The OP will see it clearly, as I did, when I changed out my impeller.

 

[Bt Doctur]

Re: Overheating after first day launch

Bravo inpellers are engine mounted,so your saying you close off the seacock and pull from the drive????????? Going from 1 - 1/4 to 3/4

 

[scoflaw]

Re: Overheating after first day launch

No, close off drive, and pull from seacock. Trying to pull from drive fried my impeller as well, even though seacock was closed.

 

[jkru]

Re: Overheating after first day launch

No, close off drive, and pull from seacock. Trying to pull from drive fried my impeller as well, even though seacock was closed.

Did you run the engine above idle during that time? If so that would do it.

Also how do you close of the drive? Tape or somthing like that?

Also I found out what was wrong and why I overheated, the heat exchanger was empty. They told me they didnt know why so I told them to run a pressure test. After they found that some hose had come loose and there was some miscomunication prior to running the pressure test; Ill find out more today.