Engine Corrosion..What is This?

[tperk100]

While doing some routine maintenance I noticed this spot of what looks like salt water corrosion on the engine. I cleaned the corrosion off to get a better look. You can see the remnants of the corrosion in the pictures.

As the pictures show there is a small round indentation in the casting about the diameter of a pencil. This area seem to be soft /flaky when I probe it. There is no such indentation on the other side of the engine.

I am hoping someone smarter than me can look at these pictures and tell me what is going on here. I really hope it is not what I suspect.

Thanks for any assistance.

[99yam40]

sure looks like a hole corroded through the block from the inside

[tperk100]

Does this mean a new engine?

[Windknotnc]

Are you having any problems with the engine? The round circle looks like a casting mark, but the small darker area above it looks like a small hole. How well have you cleaned the area? Use a small brass bristled brush to clean it off good and remove all the corrosion. If you have a hole in it you will need a new block. If you have a hole you will have no or significant loss of compression in that cylinder. I think you will know if there is a hole by how it runs.

[ausnoelm]

I think you will find that hole is in the water jacket, so as such, there will be no compression loss, the motor will run fine, however, the hole will get bigger and bigger untill the block is unusable, you may be able to clean it really well and fill the hole with some sort of alloy filler. (maybe)

[tperk100]

Thanks for your responses.

[Tucker]

Put some Marintex in the hole and be done with it. Or, shell out the bucks...

[tperk100]

After removing all "soft" metal I ended up with a 1/3 inch hole in the water jacket. I further dressed the hole with a tapered dremel stone bit. I used my dremel to wire brush the surrounding area, and then I cleaned all with acetone.

I then applied a liberal dose of quick setting JB Weld. I have to say that the repair LOOKS real good! We will have to see how it performs, but that probably won't be until spring time.

Thanks to all for your help.

[99yam40]

I would think the expanding and contracting of the metal and the JB at different rates from the heating and cooling will not allow it to keep a good seal.
But time will tell

[tperk100]

PROBLEM SOLVED -

JB Weld did not hold up for even one trip. $3550 for re manufactured powehead fixed the problem.

Thanks for all your suggestions.

[Tucker]

How did the swap go tperk? Everything fit back on without any problems? Good to go for a couple thousand hours more right?

[tperk100]

The dealer did not mention having any difficulties at all. The parts and labor warranty is for one year. Seems to be running fine. Have put about 60 hours on it so far. Will probably last me until i am ready to quit boating just due to old age......hopefully a few thousand hours!