Despite the additives refiners put in their gasoline to keep engines clean, and regardless of where you store your outdoor power equipment, the chemistry of gasoline (actually a blend of many different compounds and molecules) is such that it doesn't keep well.

The problem is even more acute when gasoline sits for more than 30 days in cold weather when condensation can form on the inside of fuel tanks and storage containers. Water causes rust and corrosion, aged gasoline thickens and causes varnish deposits, and sure enough, in the spring when you try to start poorly-winterized equipment you have a carburetor to clean. (That's after you get a krick in your back from yanking repeatedly on the starter rope thinking: "One more pull and it'll fire!" Yeah, right!)

Briggs & Stratton has some tips for you this fall that will save you lots of profanity and muscle soreness next spring, and it revolves around keeping fuel systems clean throughout the winter -- particularly on unused equipment.

Those tips include:

1. Drain the fuel tank and fuel lines of winter-idled equipment. Run the engine until the carburetor float chamber is dry. (You can add the drained fuel to your car's fuel tank as long as your car's tank is more than half full with no problems, according to EPA recommendations). Another good bet, though not as sure as draining the system, is to use a fuel stabilizer in your equipment's tank before storing it for the winter.

2. Small equipment fuel tanks are capped with ventilated caps, so remember there is still "open air access" to the fuel tank, even when the engine is idle. B&S says you can save some problems with corrosion and condensation by putting a piece of aluminum foil over the fuel tank opening and then tightening the fuel cap down over that. The seal will prevent humidity from entering the tank during the winter.

3. While you're maintaining the fuel system for the season, B&S recommends changing the crankcase oil to flush out combustion deposits and any sludge that might have built up through the previous season. Also, it's a good time to replace the spark plug with the recommended model and heat range, and just before you do that, squirt a couple of teaspoons worth of clean engine oil into the cylinder to prevent rust and corrosion until spring.

4. Fall is also a good time to clean the air intake area, the carburetor, and to replace the air cleaner element. While cleaning those areas, be sure to clean any debris from the engine's cylinder and head cooling fins.

5. Finally, before you put the engine away until spring, slowly turn the crankshaft until the piston rises to near the top-dead-center position (when you feel compression against the starter rope). This ensures both intake and exhaust valves are closed -- which stops outside air and humidity from entering the cylinder during storage.

It's all common sense, and it's all been said before, but you'd be amazed how many perfectly good engines will get scrapped next spring because they wouldn't start -- and these simple steps will prevent that in most cases.