Somebody Explain this to me Re: T-Stats Question

[zenoahphobic]

Although some water has passed in this thread (pun intended), I still have a few points to make.

I'm not overly convinced that the thermostats don't open. The infrared reading is more the outside cover temperature than the inside water temperature. The lower the temperature or the closer we get to ambient outside temperature, the closer to actual "block" temperature it becomes, and not the temperature of the water somewhere behind.

The water flow past the thermostats with engine running on muffs hasn't been measured.

So there are only assumptions not verified.

Salt laden water rises above fresh water. So the theory of it depositing this way has some merit. It wouldn't keep caking up harder and harder, as mentioned earlier, it will cyclically mostly redissolve at every full warm use of the engine.

However that aside the OP is looking for a better flush. In this regard I'm all for some form of a bypass attachment/tube. This drilling of holes in thermostat want produce enough flow without seriously compromising their function. You might as well put in a lower opening temperature thermostat to be more effective. You will need to search for such that have more satisfying opening "curves". The OPs location may warrant such modifications.

I'm very disposed to proven modification solutions to all sorts of design failings, but sadly very little experimentation or mods exist for outboards generally.

[pstephens46]

Although some water has passed in this thread (pun intended), I still have a few points to make.

I'm not overly convinced that the thermostats don't open. The infrared reading is more the outside cover temperature than the inside water temperature. The lower the temperature or the closer we get to ambient outside temperature, the closer to actual "block" temperature it becomes, and not the temperature of the water somewhere behind.

The water flow past the thermostats with engine running on muffs hasn't been measured.

So there are only assumptions not verified.

Salt laden water rises above fresh water. So the theory of it depositing this way has some merit. It wouldn't keep caking up harder and harder, as mentioned earlier, it will cyclically mostly redissolve at every full warm use of the engine.

However that aside the OP is looking for a better flush. In this regard I'm all for some form of a bypass attachment/tube. This drilling of holes in thermostat want produce enough flow without seriously compromising their function. You might as well put in a lower opening temperature thermostat to be more effective. You will need to search for such that have more satisfying opening "curves". The OPs location may warrant such modifications.

I'm very disposed to proven modification solutions to all sorts of design failings, but sadly very little experimentation or mods exist for outboards generally.

A reasonable man, this Zeno.

[HMBJack]

Yes indeed Zeno.

You make some excellent points - none of which I can disagree with.

Still, you can't deny the salt build up in the "as is" system after my 1 year and 270 hours. And I flush routinely.

I'm so passionate about this because this is the 2nd time I'm seeing this salt build up in the bores (starboard side mainly).
I saw it a couple years ago when I first pulled my T-stats and was horrified. This 2nd time is simply more of the same.

My modified T-stats (4) are installed on my twin F250's. I have another set handy in case I observe any - and I mean any - operating issues. Only takes an hour to swap them out with my 10mm.

I will report back in July or August and share my results. I'm happy to be the guinea pig!

Personally - if there was a really good design in FW flushing for these engines, I think they could last for 20,000 hours.

In the end, I hope this thread is helpful to all who read it. I got a lot out of it and hopefully so did you.

[99yam40]

Salt laden water rises above fresh water. So the theory of it depositing this way has some merit.

I am curious how you came up with this.

here when the rivers run hard and fresh there is salt layer on the bottom of the river with the fresh running over it

[boscoe99]

I am curious how you came up with this.

here when the rivers run hard and fresh there is salt layer on the bottom of the river with the fresh running over it

He is in Australia. Where his up is our down.

[rodbolt17]

this has got to be the dumbest thread I ever posted on.
when you use the onboard flush the water has two paths.
up and out or back through the pump housing.
unlike the closed cooling system in your truck, this system must bypass a certain amount of water.
your at a dead idle trying to use cold water that is NOT recycled and your doing it on 200+pounds of an incredibly good heat sink.
you will most likely NEVER get the block past 150*F on a flusher.
simply aint gonna happen.
yam and merc never went on a joint venture with a 250.
back in the day when jonnyrudes went to an opening t-stst on the cross flows we had overtemp issues when first started.
cause the T-stat would not bypass water.
that discussion is why I got banned from another site.
it is called maintenance, why not simply do it?

[pstephens46]

If we keep this thread going, we are liable to drive Rodbolt batshite crazy.

[boscoe99]

this has got to be the dumbest thread I ever posted on.

Thank you for your contributions towards the dumbest post ever.

Do two dumb remarks = one smart remark?

[zenoahphobic]

I am curious how you came up with this.

here when the rivers run hard and fresh there is salt layer on the bottom of the river with the fresh running over it

Now that is interesting.

I've not looked this up for a while, but the sea is saltier at the top than at the bottom. At least in the deep sea it is.

I suspect the fresh water flowing over the top of a river flow is because it has not properly mixed with the existing water, rain water literally enters the system by flowing onto the top.

Now there is also the colder the water is the more salt it can hold in solution which does seem to support your river scenario.

Density is the key here.

[zenoahphobic]

Thank you for your contributions towards the dumbest post ever.

Do two dumb remarks = one smart remark?

Yes, just like numbers if you keep adding to a negative number you eventually get a positive number......just.as a collection of seemingly dumb remarks eventually strike the truth.

[zenoahphobic]

Robolt touches on the problem about thermostats, they actually need water to flow through them to work properly.

It's to do with thermal conductivity, and they are best suited to a circulatory system that uses steady feedback.

That is a system where the engine overheats, this in turn overheats the water which is then transported (circulated) to the external radiator where it is cooled then it is transported to the thermostat to measure the temperature and accordingly opens to increase the flow through the engine. The system uses a large volume of water and pressure to "smoothly" regulate the temperature.

An outboard does not do this quite this way, it uses a small amount of unpressurised cold water and uses the immediate water from the engine to do small flow adjustments.

[99yam40]

Robolt touches on the problem about thermostats, they actually need water to flow through them to work properly.

It's to do with thermal conductivity, and they are best suited to a circulatory system that uses steady feedback.

That is a system where the engine overheats, this in turn overheats the water which is then transported (circulated) to the external radiator where it is cooled then it is transported to the thermostat to measure the temperature and accordingly opens to increase the flow through the engine. The system uses a large volume of water and pressure to "smoothly" regulate the temperature.

An outboard does not do this quite this way, it uses a small amount of unpressurised cold water and uses the immediate water from the engine to do small flow adjustments.

Seems I remember the automotive motors having the stats on the output of the motor before hitting the radiator for cooling.
they kept the flow down to a trickle until the motor warmed up the water in the motor enough to open the stat so water could be cooled by the radiator

[zenoahphobic]

Seems I remember the automotive motors having the stats on the output of the motor before hitting the radiator for cooling.
they kept the flow down to a trickle until the motor warmed up the water in the motor enough to open the stat so water could be cooled by the radiator

Nothing wrong with your memory you indicate the direction of flow in many engines. I think the design rationale was to push the "rising" heat down through the radiator where the radiator is mounted vertically. I imagine it was thought that at slow flow rates that if the flow was from the bottom to the top in the radiator (not engine flow) that the heat dissipation is less efficient.
I guess convenient physical placement of hoses and the bonnet height had something to do with that convention, together with the "safety" of introducing cooler water to a region where the engine is not as hot first. (But it makes more efficiency sense to do this the other way around, as heat travels quicker the greater the temperature diffence between the water and metal is.
Increased cooling system pressures as cars modernised, increased the coolant temperature before it boils. The apparent need for this was to reduce the volume, and therefore the weight of, water required, and to allow the engine to run hotter to burn off more nasties in combustion ( although obviously one could easily have restricted the flow to do this).
They didn't care if car reliability was compromised. Cars now, when they overheat, do so very rapidly before detection and damage can be avoided!

[HMBJack]

News Update:

After using my F250's for over 50 gallons since I installed my modified thermostats (see photo), I'm happy to report that ALL IS WELL!

No effect whatsoever on performance or economy (nMPG).

And I have every reason to believe my freshwater flushing is doing a MUCH better job cleaning my T-stat housings thanks to the weep holes I drilled.

I'll report back in the Fall when I pull and inspect my T-Stats and housings.

Curious if the paint I applied to the copper sides of the T-Stats minimizes the crude which develops in there by competing metals (Copper Vs. Aluminum in a wet and salty environment).

No, I don't think I'm smarter than a Yamaha Engineer - just sick of discovering a FW Flush with the current T-stats doesn't really flush or clean anything as illustrated and commented on in the above.

[BQUICK]

Here is my prototype flusher for 89 200hp. Flushes from T stats down with motor off. Replace cap after flushing and leave it dangling.