We have a 32 Endeavour powered by a Yanmar 2QM20H engine with a Kanzaki-Carl Hurth KBW10 Reduction and Reversing Gear system. The lock nut that holds the output coupling to the output shaft on the KBW10 has reversed itself and the coupling as pull back off of the output shaft (spline). I have threaded it back on but do not have the output wrench to tighten the nut to the specific torque of 68.7 ft. lb. I did get it finger tight and took a small chisel and tapped it tighter but cannot tell (limited space between the couplings) whether it will hold. This has happen to us once before and I performed the same procedure along with “caulking” by center punching the nut, this did not hold. Can you help me with this issue?