Mariner 4ML 2 Stroke Overheating

Hi! I am new to the forum and excited to be here.

I replaced my impeller when I found the motor was overheating, and several impeller blades broke off. I cleaned all my water pipes, tstat housing, found some plant debris near the tell-tale outlet, and I have removed the power head and have done everything short of opening the crank case (I went through all this effort because I thought something up top was the problem).

I stuck the lower unit in a bucket with the pickup tube to see if I could get water to the top of the tube by (I know, go ahead and cringe) placing a drill on the drive shaft splines. I discovered that water gushes out the top of the impeller housing (where the crankshaft goes through) rather than traveling up the pickup tube. I ordered a new impeller housing and gaskets, and still have the same problem!

I have scoured the lower unit parts diagram on this website for my motor, and I feel like I have all the pieces--what thoughts do you have?

I'm sad that I'm grounded, I missed the bass spawn here in northern Utah

Also, I wanted to post a pic or two, but I can't figure out the black magic to upload an attachment. I choose a photo and upload it, but it doesn't show up.

6/14/2021 UPDATE:

The motor is fixed!!! I had gone through all the necessary things that would cause the motor to overheat, but I was not thorough enough with one of them.

I removed the water pickup tube, ran weed whacker twine through it, and ran water through it. Those tests worked fine. After going through everything else and feeling exasperated with no ideas left, I decided to jet some water through it from the garden hose (when I had only trickled water through the tube in the kitchen sink). Lo and behold, it works!

No one responded to my post, but I hope this can be an example for anyone who reads this: just because you worked on something does not mean you did it right; don't be afraid to circle back and try the same thing a little more in depth and it may fix your problem. Plus, debris may move around each time you run the motor, so you may need to check things multiple times.