Stuffing Box

01/26/2014: Adjusted only. The rubber boot needs replacing eventually.

1. Adjusting the stuffing box.
   1. The stuffing box will sometimes start to drip too often introducing water into the bilge. Or maybe it somehow went out of adjustment and is getting too hot. In either case you must adjust the pressure against the stuffing around the prop shaft.
      1. The stuffing should be loose enough to allow cooling seawater around the prop shaft but not loose enough to flood the bilge.
      2. It should also be tight enough to create a good seal but not tight enough to burn the stuffing.
      3. A perfectly adjusted stuffing box should allow the least amount of drips while remained only slightly warm to the touch while operating continuously at cruise power. You should be able to grab the adjusting nut with your hand for an infinite time without discomfort.
      4. One drop of water every 10 to 60 seconds is normal.
   2. Stuffing box details.
      
      

      Looking aft where the prop shaft exits the hull. The rubber boot is missing the 2 hose clamps. Water would be gushing in if the boat wasn’t currently hauled out.

      1. The prop has parts attached to it. From the prop forward you will find:
         1. The prop
         2. The cutlass bearing
         3. The through hull
         4. The stuffing box stationary nut
         5. The stuffing box stuffing inside the stationary nut
         6. The stuffing box lock nut
         7. The stuffing box adjustment nut
         8. The engine
         9. There is also a rubber hose fitting hose clamped around the gap between the stationary nut and the hull. If this fails it will fill up the boat with water quite quickly and should be double hose-clamped.
   3. Adjust.
      1. To adjust the stuffing box adjustment nut first loosen the lock nut.
         1. Use two plumbers wrenches (or a pipe wrench, but the pipe wrench can chew up the metal) to hold the adjusting nut while loosening the thinner lock nut.
      2. Then use one wrench to loosen or tighten the adjustment nut.
         1. Only a 16^th of a turn can make a difference.
         2. If the shaft turns, you should be able to hold the transmission section with your hand while adjusting.
         3. If the whole assembly turns around the shaft, you may need to use a pipe wrench to hold the stationary nut.
         4. As a rough first adjustment, loosen until you can turn the shaft by hand with some difficulty. While testing, the adjustment will be refined.
      3. Then tighten the lock nut snugly, even while testing.
         1. If the lock nut is loose at all, it can allow the engine to unscrew the adjustment nut very quickly!
   4. Testing
      1. Run the engine in slow forward and note the dripping.
      2. If there is no dripping, feel the stationary nut for heat.
         1. If it starts to heat up with no dripping it is too tight and may cause damage to the stuffing. Put the engine in neutral with no delay.
      3. Once the stuffing box is adjusted so that it won’t overheat, increase engine speed and start counting the number of seconds between drips. Periodically feel for overheating as you test.
      4. Put the engine in neutral between adjustments for safety.
      5. Once satisfied, ensure the lock nut is tight, the rubber boot has 4 hose clamps in good condition, and go motoring.
2. Adding stuffing.
   1. ?
3. Replacing stuffing.
   1. ?