New Manifolds Installed - Overheating now..........Any ideas?

[sfakeith]

So I installed new manifolds on my 2005 MCM 5.0 Dry-joint motor. I hooked up the hose and cranked her up and all was great, no leaks. But after 20 mins of running the motor in the driveway I started to notice the temp creeping up. It usually runs in the 160 range but when I saw 200 on the meter, I shut her down and facepalmed. I've never run it that long hooked up to the hose and am wandering if not enough water is getting through the system. Anybody else experience this???

I'm also hoping that I didnt install the gaskets in the correct order. According the the service manual:
The picture is of my motor's riser's. Mine, however, are neither the 3 inch or the 6 inch as stated in the manual. Also, I cant tell if they are warm or cold risers. Any help???

 

[Don S]

Re: New Manifolds Installed - Overheating now..........Any ideas?

What is the serial number of your engine? Is it all factory, or has the cooling system been changed.

Your gasket pictures are too small to seek, load the image, not the thumbnail when posting pictures.

Might help to post an overall shot (picture) of your engine so we can see how it's plumbed.

 

[sfakeith]

Re: New Manifolds Installed - Overheating now..........Any ideas?

BTW, This is how i installed the gaskets:

 

[sfakeith]

Re: New Manifolds Installed - Overheating now..........Any ideas?

serial number is OW328719

 

[Don S]

Re: New Manifolds Installed - Overheating now..........Any ideas?

Look at this picture, is this how your cooling system is plumbed? Be sure, don't assume.
Look at the thermostat housing, and where the hoses go.

 

[sfakeith]

Re: New Manifolds Installed - Overheating now..........Any ideas?

Yes, that looks correct.

 

[MarkSee]

Re: New Manifolds Installed - Overheating now..........Any ideas?

I'm not going to be able to add any technical ideas but while it was running before you saw the elevated temperature, did you happen to notice the flow of the water out the idle relief ports being less than normal?

Once I noticed the flow just didn't seem to be normal and found a slight kink in the hose that restricted flow a bit.

As far as running 20 minutes on a hose: I routinely run 15 minutes slightly above idle with no issues.

Mark

 

[Fun Times]

Re: New Manifolds Installed - Overheating now..........Any ideas?

BTW, This is how i installed the gaskets:
View attachment 180985

It appears like your restricted gasket is in the wrong spot, it should to be on top not the bottom.

Right now your set up for cold, you should have warm according to your serial number. See Page 7D-3 in S.M #37.

It also appears as if you now have the 1.7 inch riser extension kit, not the 3 inch that may have come with the engine when new according to your serial number.

 

[sfakeith]

Re: New Manifolds Installed - Overheating now..........Any ideas?

It appears like your restricted gasket is in the wrong spot, it should to be on top not the bottom.

Right now your set up for cold, you should have warm according to your serial number. See Page 7D-3 in S.M #37.

It also appears as if you now have the 1.7 inch riser extension kit, not the 3 inch that may have come with the engine when new according to your serial number.

I bought the boat new in 2005 five and have never had anything done to it. Do u think having those gaskets backwards is what's causing the overheating?

 

[mikeav85]

Re: New Manifolds Installed - Overheating now..........Any ideas?

i just put in new manifolds and riser. i don't have extensions on mine but did ask the mercruiser shop what the second pass thru flow gasket was for. they told me if i needed to put in extensions to make sure the open gasket was on the bottom and the restricted was on top as though the extension was never there.