Scx upper unit, paint blistered
 

So after a hard run 75miles give or take at around 4500rpm, I noticed when I got the boat back on the trailer that the upper units paint was "blistered", looks like an overheat problem. I know that they have an internal drive shower. I tried blowing air through the port and air won't come out the drive. Pulled the upper bearing cap carrier and saw no discoloration in the gears and or bearings. Also oil didn't seem to smell burnt. Some minor metal pieces on the magnet but it's been the same every oil change. Drive has about 80hrs on it. I'm going to split the upper from the lower to see why the water inst traveling to the cooler. The motor is fed also through the drive and shows no sign of restriction or running hot. Does anyone have any thoughts ? Is there an internal pump? I haven't taken an scx apart before. Anyone have a schematic on it, I tried calling Imco and they of course weren't any help besides telling me to send it in for a 8k rebuild. Typical. If someone could chime in and throw some ideas at me that'd be sweet.

Sorry I'm of no help as I have an Extreme SC upper and mechanics do the work. But here is a link to the manual for the SCX - Attachment 571141

Assuming an SCX lower, the passage that feeds the drive to cool it is in front of the main water passage. Make sure that port is open. On the SC lower it is plugged if you don't have an SC upper. Customer of mine put an SCX upper on an SC lower and didn't remove the plug. He didn't run it that long before he put it up for the winter and cracked the case because water was trapped above that area. Split the upper and lower and try an blow air in both directions to make sure the passages are open.
Hope that helps!
Dick