Somebody Explain this to me Re: T-Stats Question

[HMBJack]

Zeno - as to the temperature thing - here it is again (below). I will estimate the air and dockside hose water temps to be about 50 degrees I'd say.


Here is a little experiment I performed today with my boat up on a lift:
1. Connected FW hoses to a set of muffs as well as to the garden hose fitting at the base of the powerhead.
2. Started the engine and let it idle in neutral which is about 600 RPM's.
3. With a digital heat sensing gun, during every minute of run time, I measured the temp of the starboard side T-Stat housing (outer casing where the T-stat sits inside).
4. Temperature was 74 degrees before I started the engine then it rose to 88 after 2 minutes then ranged between 90 and 98 until I shut off the engine after 20 minutes.
5. I repeated the above 4 steps on the other engine and experienced similar results. Temp range was 91 to 109 over a 17 minute run time on muffs + garden hose fitting.

When I returned home, I took a set of identical T-Stats I had removed from my F250's and placed them in a bowl of water measured at 100 degrees per a digital mouth thermometer.

None of the T-stats opened at 100 degrees. I warmed the water up to 109, my highest reading while idling, and again, none opened up - not even partially. They of course all opened when exposed to boiling water (~212).

This all makes sense since the T-stats for an F250 is set to open at 158 degrees.

[zenoahphobic]

I am the Original Poster and I do not think this is the dumbest thread.

I tested my engine at idle and found the thermostat cover ranged from 90 degrees to a high of 109 over a 17-20 minute test.

The T-stat on my engine doesn't open until it hits 158. So, I can only conclude the T-stat remains closed while flushing on muffs.
Panasonic (?) took the time to measure the water that the bleeders pass and found it was only a 1/2 gallon over 10 minutes.

My point is flushing - no matter how you do it - does NOT really flush the T-stat bores which are up high on the V6 four strokes) 3.3L).

I flush all the time and the photo I posted is after 270 hours. I'm telling you the t-stats remain closed and those pathetic bleeders are just that - pathetic.

If you think you're really flushing salt out of your T-stat bores while at idle, don't take my word for it.
Get your 10mm socket out and pull your t-stats and tell me what you think then.

Might be time to refocus on the temperature thing.
How did you take the thermostat temperature, couldnt find how on rereading thread?
My concern is that this doesn't represent the coolant temperature, or more poignantly the actual temperature of the thermostat "bulb".
There is a lot of engine mass to heat up, and conversely a lot of surface area to dissipate heat. At idle the heat energy produced is little and as a percentage compared to the engine running at full load, a lot more of this heat goes out with the exhaust.
Now the critical thing here is the ambient temperature and the water temperature. Conceivably, at low enough temperature , the heat produced balances the "natural heat" dissipation of the engine and the water (just sitting somewhere up the block) without the need to actually have much circulation at all.
So the pertinent questions are how cold is the air and water?
The thermostats may actually be open, or the load must be increased and/or the motor run for a longer time. No other reasons possible.

[HMBJack]

I am the Original Poster and I do not think this is the dumbest thread.

I tested my engine at idle and found the thermostat cover ranged from 90 degrees to a high of 109 over a 17-20 minute test.

The T-stat on my engine doesn't open until it hits 158. So, I can only conclude the T-stat remains closed while flushing on muffs.
FairDeal took the time to measure the water that the bleeders pass and found it was only a 1/2 gallon over 10 minutes.

My point is flushing - no matter how you do it - does NOT really flush the T-stat bores which are up high on the V6 four strokes) 3.3L).

I flush all the time and the photo I posted is after 270 hours. I'm telling you the t-stats remain closed and those pathetic bleeders are just that - pathetic.

If you think you're really flushing salt out of your T-stat bores while at idle, don't take my word for it.
Get your 10mm socket out and pull your t-stats and tell me what you think then.

[pstephens46]

So what I am getting from this whole discussion is the following. If you have said engine on the boat sitting in the water tied to the wharf, start the engine and let idle for say half an hour that the thermostats will never open? Is this correct? The engine at idle, with just the WP supplying water as per normal, will not produce enough heat to open the stats?
Yes, No, maybe so?

I believe the OP ran his "test" with muffs etc. I recall the stats begin to open at a temp of 140 fully open at 158. I am not looking at the particular engine data at moment. Betting they were opening somewhat if not 100%. If the stats didn't open at all in 20 mins what do you think would be the outcome?

[panasonic]

So what I am getting from this whole discussion is the following. If you have said engine on the boat sitting in the water tied to the wharf, start the engine and let idle for say half an hour that the thermostats will never open? Is this correct? The engine at idle, with just the WP supplying water as per normal, will not produce enough heat to open the stats?
Yes, No, maybe so?

[pstephens46]

thankfully we don't have any "battery" or "charger" threads here.

those are guaranteed to bring out the apex of cluelessness

other than the "which boat/engine is better" posts (I assume - since I decline to look at them)

Can't resist the urge to pile on regarding The Whole Turd. My personal favorite was the lower unit thread regarding pressure testing. 4-5 of the regulars stating they ALWAYS vacuum test as well. Not a damn one of them would respond as to whatever standard would be used to run this test. One of the fellers over there said vacuum testing is "just good physics". As opposed to bad physics? Yam engineers employ bad physics apparently.....

[pstephens46]

I think the OP might be mistaken in saying his thermostats do not open while running on muffs. Like I said before, the stat on my motor will open and close on muffs/flush port. Water runs warm for about 20 seconds and then cold. Hard to believe his never open.

[99yam40]

I would think it does not shove as much water into the motor as the water pump would.
Maybe that would let the motor warm up enough to get the stats to open.
just my thoughts

[fairdeal]

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

thankfully we don't have any "battery" or "charger" threads here.

those are guaranteed to bring out the apex of cluelessness

other than the "which boat/engine is better" posts (I assume - since I decline to look at them)

[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.