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Thermostat Housing corrosion, BF90D

S

Seachaser

Regular Contributor
2007 Honda BF90D HP

Found leaking water from corroded thermostat housing area. It looks like aluminum corrosion is where O-ring sits. The one from the main Cylinder block behind the Electronic Parts Case.. I'm Looking for best practices to fix this.

I'm thinking clean with scotch pad first, aluminum acid wash then use marine slow cure JB weld. I'm not sure of best acid wash?

From The Cylinder Block, It's the Thermostat area Item #9,
http://www.boats.net/parts/search/Honda/Outboard%20Engine/2007%20and%20Later/BF90DK0%20LRTA/CYLINDER%20BLOCK/parts.html

Please note i have not yet cleaned the housing area:
ThermoHousCorr.jpg
ThermoHousCorr2.jpgThermoHousCorr.jpg
 
Last edited:
Use Durbans formula you will find it on i boats .com forums under the Johnson section . Type in Durbans nitric acid it should be in there with photos .
 
Tegweni said:
Use Durbans formula you will find it on i boats .com forums under the Johnson section . Type in Durbans nitric acid it should be in there with photos .
Click to expand...



I had the same issue on my 225, posted a thread on here a few years back. After trying several solutions I settled on JB Weld SteelStik. Don't be shy with it, I found putting as much as you can fit on the void keeps it from springing a leak.

Have about 300 hrs on the fix, so far so good.
 
Did you do anything special to clean the surface? Any acid wash?




Other Line said:
I had the same issue on my 225, posted a thread on here a few years back. After trying several solutions I settled on JB Weld SteelStik. Don't be shy with it, I found putting as much as you can fit on the void keeps it from springing a leak.

Have about 300 hrs on the fix, so far so good.
Click to expand...
 
Could you use industrial strength toilet bowl cleaner? It has sulfuric acid? Just use it carefully for a short time, then again as many times as you think it needs. Wash after each use with water to remove all residue. I know it works on steel and will remove all rust there. You could test this on another throw away piece first?
 
You can buy it at your chemical shop that sells chemicals ,make sure you read the chemical safety sheet they should supply you can buy it in 70% strength ,use a little paint brush and apply on the area you want to clean leave it for 10 to 20 mints or longer then hose or wash of with water , you can mix it with water in a drum to flush your motor the stronger you mix it with water the better the results idle for about 1 hour , salt away doesn't do my job iam sorry ive desalted 1970 motors were the salt was hard as crystals , be careful there was a fella on i boats that used some other stuff the result was no good ended up with a hole in a part ,my Honda 17 years old does not have any salt deposits in it after i cleaned it up.
 
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