Cooling System???

[GT1000000]

Serial Number 5875380...Mercury Black Max, circa 1980-82, V-6, 200HP...Give or take from all available sources...:watermelon:

According to the diagram below, water should flow up from the water pump to the Exhaust manifold covers, then around the cylinder walls and out through each of the thermostats and the poppet valve, then finally into the exhaust, tell tale and water discharge...

Now, my question is...
If I put on muffs, and I turn the water on, AND...I removed the thermostat housings...shouldn't the water begin filling the engine and eventually flow out of the thermostat housings????:noidea::noidea::noidea:
What am I doing wrong or what is going on?
I believe I have eliminated the possibility of a bad impeller and/or blockage in the system as I have just come in from the 100º sweltering heat outside, after spending about an hour and a half removing the lower unit, disassembling the water pump to check the impeller and flushing all the water passages with full water hose pressure and water flowed freely from the t-stat openings, both forward and reverse...I also blasted water through the water intakes on the lower unit while it was off and had water coming up through the pump housing...
I just put everything back together and even with the water turned on and while cranking the engine there isn't any water getting up into the water jackets...???
Very confused and I would appreciate any insight...
Thanks!

 

[sam am I]

Flexible Impeller type water pump combined w a lil loss due to a small vent bypassing/leaking!!.....If you can/could seal the muffs better to increase the pressure and FORCE the water by the normally closed vanes, it probably will at some point/pressure and volume. The volume between a set of the vanes actually changes due to the geometer of the housing, offset of impeller and rotation about the housing, so even cranking isn't quite enough(probably close tho) while on the muffs......just guessing tho, not an expert at hydrodynamics

 

[Dukedog]

Ok,is this include t-stats? Just crankin', not runnin'?

I just put everything back together and even with the water turned on and while cranking the engine there isn't any water getting up into the water jackets...???

 

[GT1000000]

That was without the t-stats and housings installed...in other words I just left two big holes at the top of the water jacket...

 

[wired247]

If you are just cranking the engine why would there be any flow or pressure up top? The pump vanes at low speed are a positive displacement pump and act as a barrier to flow if they are not turning at operating speed at that point and they prevent the free flow of water. It sounds like you are are expecting water to fill the motor without the motor running and its just NOT going to do that.

 

[GT1000000]

Photo Update on this cooling issue...

This is what was left of the thermostats...I am guessing that is what they used to be...



These are some pics of the poppet valve...

Can you say "Restriction?"





I can run water through any of the openings left behind, and water flows freely out of the other openings and some even seems to make its way out of the water intake on the leg...?

Oh and this "thing" was being used in place of the correct bolt that should have been installed as one of the 4 that hold the water pump housing in place...



Fortunately, the threads were still intact and I happened to have the correct SS bolt to replace that "thing"...:facepalm:

 

[GT1000000]

If you are just cranking the engine why would there be any flow or pressure up top? The pump vanes at low speed are a positive displacement pump and act as a barrier to flow if they are not turning at operating speed at that point and they prevent the free flow of water. It sounds like you are are expecting water to fill the motor without the motor running and its just NOT going to do that.

OK, I suppose that makes perfect sense...
I was incorrectly assuming that it would because I was using my Tower of Power as a reference...when I hook up the muffs on that engine and crank up the water, it starts to flow from all of its orifices without even cranking...

So, that being said...
If I start the engine, with the muffs, I should see the desired effect...
Which is to see water spewing happily from all the current openings?
Thanks

 

[Dukedog]

What 24/7 said. Clean it up. Replace everything that needs ta be replaced. Put it ALL back together, add water and "start" tha motor.........

 

[wired247]

I was using my Tower of Power as a reference...when I hook up the muffs on that engine and crank up the water, it starts to flow from all of its orifices without even cranking...

Your tower of power's impeller is shot.

 

[GT1000000]

Thanks for all the help, gang...

wired247,
Because of the info you have shared me, I now have a much better understanding of how the cooling system works on these Mercs.
Truly appreciate the schooling!

It is actually kind of hard to find information on the theory of operation of most things, and now this particular part of the outboard system is much clearer.

And now that I have this new found knowledge, I totally understand the fact that the impeller was shot on my ToP...
I was referring to my very limited knowledge of how these systems worked, about three years ago, before I began my current restoration and have since acquired a complete water pump kit for installation when my tub is completed...

Well, I got the required parts to rebuild the poppet valve and the new t-stats...



After about 1/2 an hour or so, the real pain in the butt was removing the seal in the block and getting rid of all that red silicone, I got everything put back together and fired up the engine...

After running for a few minutes, the t-stats opened up and the tell tale began flowing...

I used my infrared thermometer to check the head temps and they seemed to be OK, around 143- 150 degrees F...sound about right?

If anyone is interested, I threw together a couple of goofy videos showing what I did...

Once again, Thanks for all the help...I'll post a link to the finished product when it is actually fishing in the future...

GT1M