Here's a little info that may help
I have an O'Day 35, which is very similar to the 34s. The prop shaft on mine is 1 in dia, and I suspect it may be the same on yours. You need the correct size packing, which is determined by the clearance between the shaft and the stuffing box, because that's the space you need to fill. (I'm assuming you're using standard packing, not one of the dripless materials that are now available.) On mine, I measured exactly 1/4 inch, but there was no tollerance to allow the packing to go in, even after it was lubed. So I ended up with 3/16 inch packing, and it worked fine. You'll need to remove all the old packing material, which can be a chore because of its location and the fact that it's been compressed in there for some time. There are tools for doing this, although some use an old dental pick or a small screw driver with success. (Be careful not to score the shaft in doing this.) You'll need three rings of packing material, with length cut exactly to go around the shaft and meet, preferably on a diagnal cut. (I used a 1 inch dowel as a guide, and did the cutting at home.) The packing I used (from WM) had a heavy grease that could be purchased separately to coat the material, which is suggested. The cut rings of packing are inserted one at a time in the packing nut, with the joints spaced about 120 degrees apart (i.e. not lined up since that defeats the purpose of the packing.) Start the threads of the main packing nut, and be careful not to tighted too much at first. You only want to have a drip or two a minute when the shaft is turning, and none when it's idle. If the stuffing box becomes hot to the touch when the shaft is turning, chances are it's the packing nut is too tight. Hope this helps. (There's a good bit of info on this topic on the Internet at various sites, and probably here on this board with a search.) Hope this helps.
