Cooling question

[reimelss]

I have a 1997 Merc 5.7 Block fit into my 1986 boat.

My exhaust riser on the strbrd. side has been running hot.

The manifolds and risers appear to be clear...they all pretty much look like this

My questions:
Should my risers be connected by a tube? as i do not see it in this diagram below.

Also I noticed that when pulling apart my risers and manifolds i have the gaskets required for riser kits(1.), which i do not have, instead of the gaskets in the 2nd image..see below...Would that make a huge difference?
1.)

2.)

 

[Bondo]

Re: Cooling question

Ayuh,... It All depends on which T-stat housing was used...

 

[reimelss]

Re: Cooling question

Well it looks like the one in the image above...and it was defintely on the 1997 engine.
so i am assuming this one:
Click Here

 

[Bondo]

Re: Cooling question

Ayuh,... Then it should be plumbed that way, with the gaskets stated...

 

[reimelss]

Re: Cooling question

Ayuh,... Then it should be plumbed that way, with the gaskets stated...

ok so...Im not entirely 100% on which scenario you are referring too, so to clarify...
like the image above (with no hose in between risers with the gaskets with only 2 long holes) ?
-or-
how it is currently set up (with a connecting hose between the risers and the gaskets with 4 long holes)?

 

[Bondo]

Re: Cooling question

how it is currently set up (with a connecting hose between the risers and the gaskets with 4 long holes)?

Ayuh,... I can't see how it's currently set up..

If you've got the T-stat housing in the picture above,...
You need it Plumbed, With the gaskets stated in the pictures above....

My Guess is,...
The gaskets have to many, to bigga holes, not holding the water back enough...
But that's Only a Guess...
Have you changed the Impeller lately,..??
The picture above is of a Bravo set up, is your's Bravo, or Alpha,..??

 

[CharlieB]

Re: Cooling question

Doeos your model have the plastic check ball/valves at the stat/housing where the hose begins for the manifolds?

Check for free movement and that no trash is restricting that fitting.

 

[reimelss]

Re: Cooling question

so i put the gasket shown in the picture above and it caused a "freeze" plug to pop out...
im guessing it restricted the flow of water through the riser and it built up in the manifold and then popped the plug out.

So ..replace with the 4 slotted gasket and replug and try again?

@Bond-o..its an alpha set up

@charlieB I have to check on the check valve

 

[Bt Doctur]

Re: Cooling question

Any flow should never pop a core plug, sounds like the plug may have been pushed out from freeze damage.

 

[Don S]

Re: Cooling question

Read this bulletin, it explains exactly which gaskets you should be using.

http://www.boatfix.com/merc/Bullet/99/99_10.pdf

 

[Bondo]

Re: Cooling question

so i put the gasket shown in the picture above and it caused a "freeze" plug to pop out...
im guessing it restricted the flow of water through the riser and it built up in the manifold and then popped the plug out.

Ayuh,... They're called Core Plugs, 'n sometimes they pop out when the block Freezes with water in it,...
Sometimes not...
They Never, Ever pop out because of the wrong riser gaskets,...
Never...

Click Don's link, 'n you know Which set of gaskets to use....

 

[reimelss]

Re: Cooling question

So for the past few days i have been holding my breath... I have been thinking that the therm never opened and the block never got packed with AF causing it to freeze yada yada yada.
That wasn't the case... I found the plug, and it was pushed out by the extra pressure caused by the wrong gasket...HOWEVER it wasn't the core plug that i was expecting or that you had mentioned (bondo), it was not a brass or steel plug, it was one of those rubber plunger type plugs..see the image below.
The mechanic that dropped the "new" engine into the boat used the manifolds & risers that fit the boat's y pipe..which had this plug in them...it has popped out once before, but that slipped my mind and was clouded by the thought of a cracked block.
So I guess I should put the proper gasket between the manifold and riser and then finish it off with a new plug...I am assuming to ditch that plunger plug yes?
What size plug should i purchase?
These are the manifolds that i have, but the plug i am referring to is on the side of the manifold
and does iboats have them?

Rubber plug that popped out

 

[Bondo]

Re: Cooling question

but the plug i am referring to is on the side of the manifold

Ayuh,... That should also be a metal Coreplug...
Just smaller than the 1s in the block...

 

[reimelss]

Re: Cooling question

Ayuh,... That should also be a metal Coreplug...
Just smaller than the 1s in the block...

Do you know the size of these plugs?