What Is Going On With Our IMCO Lower? After we ran a poker run I noticed on our lower IMCO. Any ideas what it is or what could be causing it? Or is this normal?

Thanks in advance.

Cavitation burn?

Someone said that today as well.

What would cause that?

are you talking about the circle spot on the side of the gear case? I ran mine for a bit the first time and it has the exact same thing

I am looking at the top and forward portion of the IMCO lower.

couldn't tell if that was flash reflection or not. Mine certainly isn't doing that. does your drive sit that low in the water when on plane?

The X dimension 15.5" and there is also an IMCO extension box with this set up.

I know the X dimension isn't the best I know but would it really lead to this? Is there a cavitation plate add on or alteration that could me made?

Mine has done the same thing, I suspect eletrolysis as the issue, was it left in the water for a couple days? I also have a pretty deep X without an extension box, I've seen this on others too

I would agree with electrolysis. When it's down in the normal position that would put it pretty close to your mercathode on the bottom of the drive housing, perhaps that is what is causing it.

The circles on the side are normal and they are welds that are made after it is cast. They all have them. As to the damage at the front; IDK. Is it corroding? Maybe it was welded up there for some reason.