When I swapped the flywheel on my 748 for a lighter Nichols flywheel, I measured my alternator and used my cnc router to make an alternator holding tool that I designed. It made the job of torquing down the big alternator nut really easy. I was asked if I could make some more of them to sell, so I did. If you would like one, I can make one for you as well.

This wrench fits single phase alternators, as on my 1998 748. Pic below. I'm informed this type is also on some 888's and 851's.



Here's the alternator holding tool I made:





This will fit over the alternator and engage on the tabs on the front of it. It's not really needed to get the nut off - an impact wrench does that nicely.

Here it is loaded on the crankshaft, ready for the nut - the alternator holder tool is engaged on the alternator:



A shot of my setup while installing my flywheel. I just had to press down on the torque wrench, and I was good to go. The holding tool made this really easy.