Somebody Explain this to me Re: T-Stats Question

[boscoe99]

this is about the dumbest thread I ever read.

Soon to be surpassed by an even dumber one.

We long to reach for the levels of dumbness displayed on TOS.

[fairdeal]

So, I take it that adequate water flows down to lube the water pump impeller with the engine running.

when supplying water via the on-board flush attachment?

yes - if you wait a few seconds to confirm that it got there, before starting the engine -- and then don't much higher than a fast idle


the impeller does a very poor job of pumping air - which is why it is not self-priming

so even though while running it is trying to pump water up the water tube - some keeps dropping back down into it

[oldmako69]

So, I take it that adequate water flows down to lube the water pump impeller with the engine running.

[rodbolt17]

this is about the dumbest thread I ever read.
remember, your at an idle with no load.
your trying to heat 200+ pounds of HEAT SINK.
DO NOT turn the water pressure down, unless you are keen on replacing the pump housing.
simply hook the hose to the onboard flusher,turn the water pressure on full(min about 40 PSI).
start the motor and let it cackle about 10 min. shut it down. go enjoy a cool refresing beverage.
BTW almost all manufacturers use the same t-stat set up. aint but so many ways to make it.
I do this every day and have for about the past 30 yrs.

[boscoe99]

Is it really simple salt that is being left behind that does not dissolve later on or is it something else?

A Google search indicates calcium carbonate and magnesium carbonate as being precipitates of salt water. Not so soluble the data says.

Maybe that is what it is. I don't know. Just wondering.

I know that I would inspect the hell out of my thermostats at least yearly or every 100 hours. And then more frequently if necessary. Inspections are free. Blocks are not.

But then if I owned a Yam again it would be an Offshore or SHO model with the new thermostat housings.

[pstephens46]

if there is just enough water flow to reach the exit port, should there still be an air pocket up above it?
I am just trying to find a reason for the salt to remain up at the stat on one side

I wouldn't think it would stay there either. Water volume should be strong enough at say 4000rpm running for a good period of time down the river to wash it away. I will say the thermostat housing gasket seems durable enough to warrant many inspections in the future without replacement. I can't really afford to buy a new block.

[boscoe99]

I would guess that with sufficient water flow all of the air should be completely purged from the system.

Now as to why crud accumulates where it does, I can only hazard a guess. Maybe each time the engine stops, some water gets trapped in the horizontal bore of the thermostat cavity. As that water evaporates it leaves garbage behind. If my theory is correct then a high time engine with low cycles (starts and stops) would be much less prone to crud build up than would be a high cycle engine. We often take engine calendar life and engine operating hours into consideration but don't make much mention of any effects that starts and stops have.

[99yam40]

if there is just enough water flow to reach the exit port, should there still be an air pocket up above it?
I am just trying to find a reason for the salt to remain up at the stat on one side

[boscoe99]

that was on a F150 and was not tilted up as the F250 was during his flushing.
in his next video I did not see anything coming out of the stat housing, strange.

I still wonder with motor tilted up causing stat area to be the highest point, where does the air go?
has to go downward to get out.
with a small amount of water flow will it be enough pressure to force the air down and out?

Air should go down and out the same passageway that water will soon follow thereafter. Assuming of course there is sufficient water pressure to raise the level of the water to the level of the thermostat exit port.

[pstephens46]

that was on a F150 and was not tilted up as the F250 was during his flushing.
in his next video I did not see anything coming out of the stat housing, strange.

I still wonder with motor tilted up causing stat area to be the highest point, where does the air go?
has to go downward to get out.
with a small amount of water flow will it be enough pressure to force the air down and out?

May need a little more clarification. Yes an F150. For some strange reason, when attached to muffs AND flush hose at same time and NOT running, no peeing or water from bore. Start the motor and water pours from both.

The obvious point is running the motor will push a hell of lot more water than the flush port.

[99yam40]

that was on a F150 and was not tilted up as the F250 was during his flushing.
in his next video I did not see anything coming out of the stat housing, strange.

I still wonder with motor tilted up causing stat area to be the highest point, where does the air go?
has to go downward to get out.
with a small amount of water flow will it be enough pressure to force the air down and out?

[fairdeal]

Where's the video?

http://www.yamahaoutboardparts.com/f...-bore-f150txrd

[fairdeal]

it may just never get any water up there.
just a pocket of air that has no where to go

No, 99 is mistaken imagining an air pocket.

The Yamaha thermostat is constructed with small bleeder vents to allow air to pass, even when the thermostat is shut tight cold.

Look at pstephens video posted today, you will clearly see the flush water jetting out of those bleeders.

[HMBJack]

it may never fill completely.

with that stat area being the highest point, it may just never get any water up there.

just a pocket of air that has no where to go

>>> Yes exactly! This supports the idea of drilling a small hole or two in the face of the T-Stat to allow air and some water to pass. Two small holes in the T-Stat probably won't affect engine operating temperature. At 160 degrees and above, the T-Stat will be wide open anyway. It's at IDLE that we're trying to accomplish flow rate to rise salt out. I never thought of an air pocket developing but that makes perfect sense. It's at the highest point of the engine. Kinda like the last scene of the Perfect Storm when the boat was upside down.

If air could be expelled, at least SOME freshwater would make it up to the highest T-stat bore (with muffs on and engine running). Thoughts?

[boscoe99]

The flush hose on the motor.