Stuffing box space problem.
Sven and all, I too had the problem your facing with our current boat. The original Yanmar 2QM15 was replaced in 1988 with the more powerful and longer Yanmar 3GMF and with that came the inability to change the shaft packing in the water. Upon one of my first haul outs I pulled the shaft and was able to shorten the log by 1 1/2", sufficient for me to now change the packing myself. By the way, I want to toss out an idea I've never tried myself yet. I envision staunching the inflow of water with the packing cup unscrewed by using part of a bees wax toilet bowl ring to stuff around the shaft and the fixed half of the stuffing box. My thinking goes along the lines of the wax hardening when it comes into contact with sea water, thereby sealing the water off and staying in place for the time it takes to repack the cup. Then when ready to reassemble it can be easily removed by first picking at and then peeling off all evidence of the wax. I've never had the opportunity to prove this to myself because years ago I installed that West Marine Drip-Less Packing Kit along with Teflon Stuffing Box Lubricant and I just can't get the shaft to leak. You might want to check to see if you have enough log length of lop off enough to solve your problem. Glyn