Thank you everyone for the great advice!
The prop is now cleaned thoroughly (not a drop of old grease remaining), re-greased with Lubriplate 130-AA, and assembled back together again, and I'd like to forward the following notes to anyone who wants to do the same and has not done this before:
1) Be sure to study the videos in detail on MaxProp
sites, they are EXTREMELY helpful.
2) Know your correct "X and Y settings" for your boat-engine combination.
3) Keep taking lots of photos during the process; before, during, and after. So you will always have a document to come back to if you need to check something.
4) When setting the "Y-mark", be sure to draw a reference line to the central hub and the spinners with a permanent marker, as illustrated here:
This is VERY important!
I almost screwed up this myself as my old reference mark had dissolved (although "permanent"), and as I was installing the blades I had accidentally moved the spinners
and thus the blades would have been completely off the correct setting, an expensive mistake!
Luckily I noticed my mistake and I had to dig out the "Y-mark" from underneath all the grease again and make a new mark.
So remember to draw that reference line when assembling, and check it is correct. And then double check.
5) I installed mine alone, but an extra pair of hands would be useful when assembling blades and end cap onto spinner. It looks easy on the video (small prop, no grease), but I can assure it's not when you have a big and heavy prop in your greasy one hand and you are feathering all the three blades with your greasy other hand, you are doing it the first time.
6) For the next time I will definitely buy and install the ZERC-KIT as I understand with this kit one can grease the prop using a grease gun. (as I mentioned on my first post, my prop is from late 80's and does not have the zerc fittings, therefore the only way to grease it is to take it apart):
ZERC INSTALLATION KIT