Thats not aftermarket..thats a red stator kit. The adapter needs DVA tested as output on blues should be 250V +. You need FACTORY service manuals to tinker with these.
If it is this style you purchased the port cylinder with wire has a trim sender unit built into it. Also the port side is the trim and starboard is the tilt side
That unit should have non preload driveshaft and upside down roller bearing. If bearing had excessive play to cause seal to leak it would have crapped the gears by now. Make sure you use correct seals and facing correct direction.
Old first generation block with mis-matched front crankcase half. Could be 150 or 175. Since front half has been changed could have blew up at one time.
There is only testing for output so make sure you have a DVA adapter and if problem found only use OEM,Serria, Rapair/CDI or WSM replacements. The cheap stuff of Amazon is junk