Skeptical III
I sincerely doubt there is enough play in the engine up/down or side/side to cause an out of alignment so bad that it would overheat and/or destroy the flax in the stuffing box. I would guess/assume that you cutlass bearing would also suffer a premature death if you were out of alignment that badly. And as previously noted, you would have one hec of a severe vibration under power if you were out of alignment that bad. Your Yanmar engine manual describes the re-alignment process. It took me about 1 hour to do the re-alignment on my shaft/engine. The Readers digest version is that you loosen the shaft flange from the tranny so you can pull the flange back and slide then slide forward so that there is a small gap between the prop flange and tranny flange. Loosen the adjustment bolts on the motor mount that allow the motor to move side to side. Loosen the 4 nuts that hold down the engine - there will be another set of 4 nuts that allow you to raise or lower the engine on the motor mount. Slide the flange toward the engine and observe. Use a feeler gage between the flange of the tranny and the prop flange. Adjust side to side and up/down until the gap between the flanges is even all the way around. Tighten engine mounting bolts, tighten prop flange bolts and voila! You're aligned. Don't forget that unless you are using a dripless stuffing box, the stuffing box must drip 2-3 drips per minute. Water helps lubricate shaft so the flax doesn't burn up.
