Somebody Explain this to me Re: T-Stats Question

[pstephens46]

Maybe measure the ID of the flush if you can/want to.

Of the garden hose?

[99yam40]

I have a feeling boscoe hit on the problem.
with the flush hose so small and trying to fill the block with the water dumping out as you fill it, 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

[boscoe99]

Maybe measure the ID of the flush hose on the motor if you can/want to.

[pstephens46]

Do that and let us know please.

Also, use just the garden hose fitting if you don't mind with the engine not running so we can see how much water flows out. Given the small diameter of the garden flush hose I can't see it being a whole lot.

I will. Not sure if tomorrow or Sunday. Fairdeal may beat me to it. Actually wouldn't be bad to see his V-6 and my I-4.

[boscoe99]

I'm stocked up on Alodine and zinc primer. I don't know if any of these flush ideas will work. Most of this residual salt crud should be somewhat diluted by running in the saltwater itself. At least moved around some. I removed my excess with a paper towel. No scraping needed. It still chewed a hole by what I assume to be galvanic corrosion.

I'm thinking of removing the cover and stat just to see how much fresh water will flow out at idle, etc.

Do that and let us know please.

Also, use just the garden hose fitting if you don't mind with the engine not running so we can see how much water flows out. Given the small diameter of the garden flush hose I can't see it being a whole lot.

[pstephens46]

I'm stocked up on Alodine and zinc primer. I don't know if any of these flush ideas will work. Most of this residual salt crud should be somewhat diluted by running in the saltwater itself. At least moved around some. I removed my excess with a paper towel. No scraping needed. It still chewed a hole by what I assume to be galvanic corrosion.

I'm thinking of removing the cover and stat just to see how much fresh water will flow out at idle, etc.

[boscoe99]

The thermostat "frame" appears to be copper or brass. What if that was covered in some sort of nitrile coating. Alodine and zinc chromate primer help. Would that prevent the battery effect by reducing the chance for conduction?

Later models have a separate thermostat housing made from a plastic type of material.

I was thinking of a large diameter hose that could run to a port on that housing. On the engine side of the thermostat. So flush water would flush backwards from the top and down instead of from the bottom and up. Half inch ID at least.

The current flush hose is too small and too long IMO to really be effective. Water being introduced into the base of the block is being lost out below while at the same time it is trying to fill and flush the block.

On the other hand, I dare guess that the vast majority either don't flush or don't need to flush (fresh water users) so maybe Yamaha things "why bother improving the system"?

[HMBJack]

it's a saltwater engine. There has to be a way to do it.

Perhaps adding what I'd call a "flush valve".
Such a valve could be sandwiched (bolted on) in between the T-stat and T-stat bore.
There seems to be enough room under the hood for this.
Then, have some kind of lever that protrudes through the base of the cowling.
Pull down, and the T-stat flush valve opens to allow water to pass.
Push up, and the flush valve closes.

[pstephens46]

What could the design engineers have done to facilitate greater water flow through the thermostats housing area to prevent or mitigate the build up of crap?

The thermostat "frame" appears to be copper or brass. What if that was covered in some sort of nitrile coating. Would that prevent the battery effect by reducing the chance for conduction?

[TownsendsFJR1300]

I have fantasized about drilling the thermo housing and pressing in a hose barb

- as from some exhaust covers -

then "tee" those into the flush hose.

That'd work!!

Do that and you likely wouldn't even have to run the engine, flush port ONLY..

I'm not sure if the LU would get a good rinse NOT running, but plumbing into the rest of the system is great!

[fairdeal]

What could the design engineers have done to facilitate greater water flow through the thermostats housing area to prevent or mitigate the build up of crap?

I have fantasized about drilling the thermo housing and pressing in a hose barb

- as from some exhaust covers -

then "tee" those into the flush hose.

[boscoe99]

What could the design engineers have done to facilitate greater water flow through the thermostats housing area to prevent or mitigate the build up of crap?

[pstephens46]

FWIW, I run my motor with two hoses. F150TXRD. 65 degree tap water. I have noticed the exhaust water "pulses" between warm and cold while idling. The T stat will open momentarily and then cool down and close. Hard to imagine the F250 doesn't heat up enough to open either t stat at all.

Even still, I have found enough of a "salt bridge" from time to time to cause some pitting in the bore.

[HMBJack]

Yes, I will certainly switch from always flushing engine OFF on garden hose fitting to flushing with muffs and engine ON now.

I suppose even though the T-stats remain closed, jamming 90-100 degree fresh water up there with the water pump pressure can only help.

I will report back on the results of this mid year after I reach 100 hours or so.

Thanks.


Lastly and FWIW, I looked at my maintenance log, and the salt in the photo up above in my first post was after 14 months and 270 hours of use flushing only with the powerhead garden hose fitting.

[panasonic]

Try just the muffs, don't turn the water on full blast, let the water pump do the work... as if the boat is tied up at the dock idling waiting to go. As Yam stated above bump the idle speed up a bit as well. I think that will work.