Take a look at the engine's overall condition. If it's really dirty, clean it with Fantastic or Simple Green, which will make it easier to find any oil, water, and fuel leaks. To that end, also clean under the engine, and line the engine bed with fresh oil-absorbing pads. Check and tighten engine belts as necessary. Start the engine and watch for anything unusual, such as excessive vibration or loose fastenings. With the engine in gear while the boat is under way, check the stuffing box for leaks or excess warmth. (See "Service Your Stuffing Box" by Steve D'Antonio, January 2008). Hold the side of a screwdriver on the shaft as it turns; if there's vibration, you could have an alignment problem or a bent shaft. (See "Play It Straight" by Steve D'Antonio, page 102.) Your spares inventory will depend on your budget and the length of time you expect to be away. At the very least, you should carry a couple of spare impellers, a full set of belts, and some pieces of hose.