Ski Boat Maintenance You Can’t Ignore

June 17, 2012
Waterski Waterski

Generally speaking, everyone knows about the importance of typical boat maintenance areas, such as oil changes and fuel filter replacements, but what about the not-so-obvious areas, such as the prop shaft stuffing box or exhaust hoses? Here are the top seven spots you won’t want to overlook.

Prop shaft stuffing box

Ignore this area of maintenance and you may just end up sinking your beloved ski boat. Therefore, at the beginning of the season, always check and adjust, if necessary, the packing to the stuffing box. The stuffing box has two basic functions: It provides a seal around the shaft to keep water from entering the boat, and it keeps the propeller shaft centered. Tighten the packing gland on the stuffing so there are only a few drops per minute, occurring when the shaft is turning. (Note: Water is required to lubricate packing, so don’t tighten to the point that there is no water dripping when the shaft is turning.) To get around this, you may want to install a dripless mechanical seal, which requires no maintenance, just an inspection once a year to make sure it hasn’t failed.


Rudder box

While you are in the vicinity of the prop stuffing box, it would be a good time to grease the rudder box and lube the steering cable. Yes, the rudder box has a grease fitting, and so does the steering cable end.

Exhaust hoses


Excess deterioration can occur with age or from exceeding the temperature limits of the exhaust hose (e.g., boat engine overheats from a failed water pump impeller), so it’s important to check the condition of the hoses regularly. If your boat engine does overheat, it could get hot enough to blister the exhaust hoses internally, which can lead to premature hose failure. Also, check the exhaust hose clamps for tightness to keep a leak from occurring.

Belt wear, proper tension and misalignment

The most common reasons for belt failure are improper belt tension (too loose or too tight) and misalignment. To check for proper tension on a V-belt, you should be able to push the belt about a half-inch with moderate pressure. To check for misalignment, align the pulleys by placing a steel rule or other straight edge in the grooves of the pulleys and align the straight edge by eyeballing it.


Engine alignment

This needs to be checked at least every 200 hours of run time or every two years, whichever comes first. Engine misalignment puts strain on the transmission seals and the shaft coupling and causes excess wear on the cutlass bearing (that’s the rubber bearing or bushing pressed inside the strut that supports the prop shaft). To get the most accurate and true alignment, it should always be done with the boat in the water.

Cutlass bearing


This should be checked about every 300 hours of run time. It can be easily accomplished by grabbing the prop shaft and moving it from side to side to ensure there is not an abnormal amount of play between the shaft and the rubber bearing. The prop shaft should feel firmly supported with very little play. A cutlass bearing with excessive play will lead to vibration problems.

Brake fluid

Replace the brake fluid on your trailer at least every two years to keep condensation in the brake system from causing corrosion (conventional glycol-based brake fluid is hygroscopic, which means it absorbs water).


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