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Acid Flushing

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"I have twin Yamaha 225 (

"I have twin Yamaha 225 ( 4 stokes 2002, 375 hours) and less and less water is going through the engines when I use the fresh water flushing connection. I have been looking for the cause for a year . ( engines running fine, no heating, water pumps replaced regularly, )Recently a Yamaha mechanic told me that this happens not only on Yamahas but other outboards too .
An acid flush should remove the deposits which block the rather small water entry hole of the flushing water. He is suggesting an acid flush.
I have had it done on diesel engines heat exchangers and monel made components but never heard of it on an outboard (aluminum?) engine.
Comments?
Thanks."
 
"Frank, have flushed engines m

"Frank, have flushed engines myself with either CLR (expensive) or simply a 50/50 vinegar/water mix. Even freshwater run outboards can scale up depending on the water they have been run in.

Have found it best if you can keep the solution in the (system) overnight if possible. Fairly easy to do on a smaller motor (simply turn it upside down) - a little tougher on a large motor.

Have found it easisest to pull the thermostat(s) and dump the solution right into the waterjacket..."
 
"use use salt-a-way when flush

"use use salt-a-way when flushing also
vinegar will work good
CLR is good

another trick we do is DAWN soap when we flush, i run it\ through the salt-a-way nozzle. only DAWN soap will work."
 
"Thanks to both of you; I have

"Thanks to both of you; I have been using salt away regularly both through the flush connection or by running the engine with the ear muffs through the water intakes, with zero improvement.
To use CLR how do you feed it into the engine? Do you use the salt away nozzle? If so, Won't it dilute it too much?
Thanks
Frank"
 
"I need to reach the upper sid

"I need to reach the upper side of the engine block to get to the area which is plugging up ( the flushing connection intake into the engine block). The thermostatts are a little lower and are very hard to reach ( lot of tubings and other connections to unhook first). I need to find a way to circuate the mixture in the upper part of the engine or through the flushing device.Have been thinking of using a55 gallon barrel and running the engine in it without the prop . Not very practical if even it fits.
Or filling a water hose with the acide mixture, connecting it to the flushing device and then running water through it which would push the mixture through.??
But I do not want to be the first one to do this; it probably means it is not such a good idea and has some "side effects".
Frank"
 
I don't think the problemi

I don't think the problemis is salt deposit but rather harder calcium type deposits in a very very small tubular area with a bend and where there is most of the time very little water circulation except when using the flushing inlet. Salt Away has had no effect since regular flushing with it has shown no improvment.
A light flushing with CLR and a weak organinic acid has had no effect.
It wouldn't have time to effect the stainless steel and the rubber components of the water pump. I have often flushed quite a few pumps on toilet systems with much stronger acids such as HCL with great success and no damage.
If I can find a thin snake to thread up the tubular bend which seems clogged I'll try. In the meantime I flush the engine through the water intake.It is running fine.
Frank
 
"Frank,

I had the same thou

"Frank,

I had the same thought about my outboard the other day, but could not come up with a way to measure how much water was running through thew motor. How did you determine that less water was running through the motor?"
 
"Tom,
I have every reason to

"Tom,
I have every reason to believe that the engines are being properly cooled and when I flush them with the ears, water flows freely and abundantly incuding through the pee holes. It is only when i use the flushing attachement which allows to flush the engine while the boat is in the water(which is convenient) that I noticed that water was not flowing properly. It was very noticeable and much worst on one engine than the other and was getting worst as time went by. All the mechanics told me not to worry and that it has nothing to do with the ability for the engine to be cooled while under way. That seems correct. But I like every thing to work right , hence my attempts to correct this.
Frank"
 
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