Propeller And Shaft

With the boat hauled out of the water, take a look at the propeller. If it shows any serious nicks or dents, you should have it reconditioned and have the shaft checked for straightness. Put the transmission in neutral and turn the propeller by hand. Does the shaft bind in any part of its rotation? This can indicate a bent shaft or severe misalignment of the coupling.

Cutlass Bearing

Examine the cutlass bearing the rubber-lined      bushing located in a strut or the deadwood of the hull. Under the normal intermittent use of a sailboat engine, it should last several seasons.

Rapid wear signifies a problem in the drive train. A barely perceptible looseness is acceptable here, but if the shaft really wiggles around, replace the bearing (Figure 1). Replacing the cutlass bearing is generally not complicated unless you are one of the unfortunates who must remove the rudder in order to remove the shaft on your boat. Normally, the bearing is simply held in place by two setscrews. Remove these and use a hardwood dowel of the same diameter to tamp out the bearing. If it’s stubborn, use a hacksaw blade to cut through the outer brass shell. Use some care in your tamping. Struts can be bent and their mounting bolts loosened if you get too enthusiastic. Be sure to get the correct size replacement bearing. You must know the diameter of the shaft as well as the inside diameter of the stern tube or strut. The replacement must be drilled partially through at the locations of the setscrews.

Stuffing Box

The stuffing box is the next component to check. Typically, a section of heavy rubber exhaust hose is used to connect it lo the stem tube (Figure 2). Make sure it’s in good condition. It should be double clamped at both ends. Inspect these hose clamps often and replace them at the first sign of deterioration. Also watch for cracks in the stern tube or surrounding glasswork.

Back off the lockout and remove the adjusting nut of the stuffing box. The section of the shaft under it will be shiny but it shouldn’t be scored or worn down; this would indicate worn packing or too tight an adjustment. If the packing seems hard, dry or crumbly, replace it. To do so, remove all the old packing with a screwdriver. Carefully measure the distance between the shaft and the inside of the stuffing box. Obtain a length of new packing of a size that fits this space snugly. Get enough to make at least four rings. Do not be tempted to wrap the packing in a spiral fashion. Cut separate rings and stagger the joints. This method requires much less tightening of the stuffing box for proper adjustment. Hand tighten the adjusting nut. At this point, the boat should go back in the water. Check the stuffing box, then run the boat under power for awhile before checking the stuffing box again. There should be a slight drip when the boat is under way. This is necessary because water lubricates this bearing. This drip should cease once the boat is stopped.