Everybody recommends Loctite for that bolt, they just disagree and/or are misinformed about which grade to use. Do research on this link........
Threadlocker: Red or blue, which one’s right for you? (loctiteproducts.com)
I don't have any mfr. recommendation for ft/lbs on that bolt, but I can say it's ft/lbs, NOT in/lbs., and you should bolt a shaft lock onto the other (flywheel) side because it's enough in/lbs that trying to hold the motor from rotating with one hand while you tighten up with the other ain't gonna be good 'nuff.
Attaching pics of a cheesy one I made out of EMT conduit, some slotted angle, and a piece of keystock all welded together for a 3/4" shaft.