When it comes to a midseason "engine" tune-up, a little effort can go a long way. Your boat's engine is one of its most important components, and regularly maintaining it will help to ensure that your boat will continue to operate efficiently throughout the summer season. Not only will some of these chores let you spend time getting to know your boat's engine, they'll also make for a smoother-running and perhaps an even less fuel-drinking craft.

SAFETY FIRST
You're working on your engines, so you're going to get dirty. Forego wearing your favorite jeans, shorts or T-shirt unless you want them to be added to the rag bag. Make sure you're not wearing clothing that can dangle into moving drive belts, etc. This goes for hair as well. Take off jewelry, especially on hands and around the neck.

You'll also - joining the long list of people who know how to make engines do what they're supposed to do - get grease under your fingernails unless you wear some kind of gloves - mechanic's gloves, for example. Failing that, Dawn dishwashing liquid and a fingernail brush will most likely do the trick.

Before you start a project, make sure you have all the tools, manuals and parts you're going to need, and make sure they're with you at your boat. If you're not on a trailer in your driveway and need to carry tools and parts to your boat, a five-gallon bucket makes a handy toolbox. Don't substitute auto parts for marine parts - they're not the same.

If at any point you have to tighten/un-tighten the battery post nuts, use a tool that can't span the distance between the positive and negative anodes, unless you like exploding batteries, burns and fused tools.

This may sound simple, but if it's running, it's either hot or can tear your finger off. Don't touch anything unless you know what it is and how hot it will be. Most importantly, don't touch anything that resembles a spinning wheel or a moving belt while it's moving.

Many of you will be working with gasoline engines. Gasoline fumes are heavier than air and will sink to the bottom of bilges and engine bays, and the vapors are more explosive than the liquid. Do not use an open flame or spark-producing tool in any enclosed space, use your blowers and - most importantly - use your nose. If it smells of gasoline, stop. If it doesn't clear with all hatches, holds, etc., open it, and find out why before doing anything else.

ENGINE CARE
If you've been using quality fuel and quality oil (2- or 4-stroke), you've already taken the biggest step toward engine maintenance. As far as outboards are concerned, you should stay with whatever your engine manufacturer recommends; there's no sense in taking a chance of shortening your engine's life-span for the sake of a few saved dollars.

Someday, you'll probably be able to purchase electronic tune-up units that can be plugged into your engine, allowing you to adjust it for power or economy, just like they have for automobiles. Until then, there are a few important  items to watch for when it comes to your engines.

To begin with, there are filters - all kinds of filters. Air filters should be changed out - with quality OEM filters - if they're getting dirty. Dirt in the air filters means a restriction of air intake, and that makes for poor engine operation on both the power and economy ends. If your engine has a flame arrestor and it's dirty, clean it out with a non-flammable solvent, and don't start your engine until it's remounted.

Other filters that should be checked mid-season and replaced if required are fuel filters and/or water separators. These prevent water from entering the fuel system (the reason for the admonition about using quality fuel). Some are large, some are small, some are separate units, and some are inline on the fuel line. Regardless, a mid-season replacement is worth the money that the filters cost. One reason this may be truer this season than others, is due to the rise in fuel prices - you may be running your fuel tank to lower levels than usual, and the bottom of a gasoline tank is where fuel accumulates water and other sludge. Combustion engines don't tolerate water very well.

Your oil filter may or may not require a change. One of the key checks before you begin is an oil check. If yours has become black, it's time for an oil change. Another indicator is the 100-hour mark: If your engine has been running for 100 hours, it's probably time for an oil filter change. Check your engine's manual or know your service schedule in case there are specific change intervals for your motor. Your boat should have an hourmeter on your tach; some have them in engine compartments. If you don't have an hourmeter, you should be keeping a log.

If you do work on your engine and/or drive, one of the smartest things you can do  - and with digital cameras, it's a snap - is to take pictures of the guts of your engine and drive, as well as the overall exterior condition, for comparison to when you're finished with the job. When reassembling the components, there's nothing better than a before and after image to verify that you've installed everything correctly.

Other than that, checking belts, wiring, leads, spark plug wires, etc., with some care, looking for anything out of the ordinary, is one of the easiest ways to pick up troubles before they start and keep your engine running clean and smooth.

GAUGE CHECK
Another operations note: You should know what the correct reading indicated by your various gauges should be. This applies especially to temperature, oil pressure and battery gauges. The latter will indicate whether your battery has the power in it to start/run your boat and if a low or non-charge situation exists, it's better to find out before leaving the dock than when you go to start the engine after that first drift through the fishing zone.

If your oil gauge is indicating a low-pressure situation, it's probably advising you that your engine is about to go. Don't attempt to nurse your boat back;  kill the power and call for a tow. It may only be the oil pressure sending unit or a loose wire thereupon, but better to be safe than sorry.

If your water temperature gauge soars, don't attempt to nurse your boat back to the dock. Kill the power ... and you know the drill. This is critically important with aluminum engines. You might be able to get away with some temperature rise with cast iron engine blocks,  but you won't get away with it with aluminum ones. Making sure raw water strainers are clear and free-flowing is essential to preventing overheating.

AVOIDING CORROSION
Due to the fact that we're in water, metal has a tendency - along with most other materials - to disintegrate over time. While fresh water is nowhere near as corrosive as salt water, it isn't necessarily friendly to metal, considering what other chemicals may be present in fresh water these days. Salt water, on the other hand, is just downright dangerous for metal and is probably why the old timers used sails instead of motors.

Outboard and outdrive manufacturers spend a lot of time and money figuring out and applying protection in the form of paint and finishes. In some cases, this can run to eight-zillion coats of different substances, all designed to keep corrosion from the aluminum that composes engines and outdrives.

You can help maintain this protection by paying attention to where you drive your boat, because every little chip in the paint is a place for corrosion to take hold. Remember, plowing is better done on land than with the lower unit of your engine. If you're a trailer boater, you should give your engine/outdrive a once-over every time it comes out of the water. Check for scratches that are deep enough to have breached the coating and - while you're not going to match the protection of factory coatings, at least attend to the area by sanding only the affected area and applying a primer meant for engines or outdrives, and then finishing with factory touch-up paint. Another caveat for saltwater boaters - don't use general bottom paint. It usually has substances in it contraindicated for aluminum. Use paint specifically formulated for aluminum outboards and outdrives.

Another form of corrosion familiar to saltwater boaters is caused by electrolysis: metals interacting (negatively) in the salt and water mix. And, yes, this can happen in fresh water. Pay attention to sacrificial anodes and change as required. Also, pay attention to any grounding wires present anywhere on or about your engine or outdrive. I've seen a complete steering system rot due to a small 5-inch, braided, stainless-steel ground wire that had broken and was left unattached.

 
KNOW YOUR LIMITS
Above all else, do no harm. Not only is  it a good thing for doctors to adhere to, it's also a good thing for those of you working on boats to adhere to as well.

Overstepping your abilities when it comes to fixing, tuning or just plain old puttering about on your boat can leave you with a shortened season. Know your limitations, and when in doubt, take your boat and its motor to an expert. If you stick to the general maintenance projects listed here, this summer will be fun from the moment you put your the boat in the water to the moment you put it up at the end of the season.