T-Stat Bore Check - Question on FW Flushing

[HMBJack]

2006 F250's with 1,475 hours.

I cleaned my T-stats and bores 14 months ago (December 2016).
Here is what one of the bores looked like yesterday.

This is the starboard side T-stat bore.
It has an alarming amount of salt build up in just over a year.
The other engine showed the same - starboard side bore had a lot more salt than the port side bore.

I flush after every trip for 10 minutes in the tilted UP position using the garden hose fitting.

Question: To flush my starboard side T-Stat bore, would I be better off flushing in the tilted DOWN position?
Or maybe flush with the engines tilted UP and turned to the right maybe?

My FW flushing seems to have no effect on the starboard side bores. The port side bores looked good.

Thanks in advance for any insight. - Jack

[pstephens46]

I don't know if tilt will matter. Is the boat on trailer or in water? Running while flushing with fresh water may help after stats open. Any pitting in bore?

[HMBJack]

The boat is lift stored. Can't easily use muffs - and nor will the T-Stats open while idling on muffs.

T-stats close within 30 seconds once hit with cold water (per my check in the kitchen cereal bowl!).

Not sure how to get that starboard side t-stat bore clean.
Ideally - I'd like to flush with HOT fresh water but that isn't a possibility for me.

[fairdeal]

because of the con rods, the heads are slightly "staggered" - with the starboard side about 1 1/2 higher than the port.
So - upright - as the water rises inside the block, it hits the port side first.

I suppose with the engine tilted up, and turned over to starboard (as if steering to starboard) that could end up lowering it.

IMO if you are going to have any chance, you need good pressure and at least a 5/8 hose - and fairly short.

My current approach is "cycling" the water on/off - I let it flow until everything is pissing real well (I have good hose pressure)

then shut off the water and let it drain away. Repeat 4-5 X.

[HMBJack]

Thanks fairdeal. Not sure why you think turning the water on and off helps.


Based on my experience with these T-stat housings - flushing is a waste of time and effort.

It's a bad design by Yamaha to disallow fresh water flow to these areas.

Yamaha says to flush - and I do - and I see the considerable amount salt build up in the above photo. Waste of time Yamaha!

Worse yet - corrosion in the T-stat bores can eventually total your powerhead. That's just great...

Only sure fire thing I can think of is to remove the starboard side T-stats every 6 months and scrape out the salt gunk that builds up.

[99yam40]

you need to be running the motor when flushing.

the stats will open up as the motor heats up.

think about it, the water pump picks up cold water from the water you are running in, and the stats open up to circulate water to the heads.
the water heats up as it runs thru the block

[HMBJack]

Okay - using muffs with engine running is worth a try. I'll try anything to minimize the salt build up. Thanks and I promise to report back at the end of this season.

[HMBJack]

in my case, it's a pain in the butt to flush on muffs as I need to raise my 14,000 pound boat on my floating lift, climb down on the hoist with the garden hose and muffs in hand, stretch out to insert the muffs on the lower unit, try not to fall in the water, climb back up off the hoist, turn the water pressure on, climb back up onto my raised boat, and start the engine. Run for 10-15 minutes to allow the T-Stats to open. Then repeat for the other engine.

I can do this but it is not nearly as easy as you guys with trailer boats.

Question - would it be beneficial to run two hoses while flushing and engine on?
Meaning - one hose on the muffs, the other on the garden hose fitting.
Like will the water flow fight against each other or flow together in the same direction? Curious...

Also - on an ice cold engine, how long would you say I need to run on the muffs before the T-stat opens?
I ask because I might do my flush procedure on the following day after fishing. Thanks,

[fairdeal]

Question - would it be beneficial to run two hoses while flushing and engine on?
Meaning - one hose on the muffs, the other on the garden hose fitting.
Like will the water flow fight against each other or flow together in the same direction? Curious...

Also - on an ice cold engine, how long would you say I need to run on the muffs before the T-stat opens?

Rodbolt has told us repeatedly that the best way to run a large Yamaha out of the water is with a hose to both muffs and the flush port.

as to how long it takes for the 'stats to open - so many variables

what's the starting temp of the engine(ambient air temp)
what's the temp of the water coming out of the hose?

in NJ - both of those could easily be 50F - in "boating weather"

in Big Pine Key - they both are often 90F

[HMBJack]

Thanks guys. I appreciate your inputs and will follow them for sure.

Fairdeal - you mention NJ - while I have lived in the San Francisco Bay Area for 35 years, I hail from Livingston and graduated from Seton Hall Prep. Summered on the Meteadaconk River as a kid. Good luck with the snow and storm you're having. Be safe!

[robert graham]

Maybe consider cleaning those bores and applying an epoxy coating as mentioned previously on these forums....

[HMBJack]

Thanks Robert.

I removed my T-stats twice in the past 14 months. Each time, after cleaning the bores up real good, I applied a couple coats of oil based rustoleum paint. If my bores degrade, I will consider an epoxy coating of some sort. At this time, only one of my 4 shows pitting - and only slightly. Hoping a regular FW flush routine - with muffs + engine ON - will keep them clear and clean.