Techs universally hear one common complaint at the onset of sled season, “My snowmobile won’t start!” Maybe the machine in question will crank over, but fire eludes the cylinders. The machine owner doesn’t understand why — it ran when he put it away and it sat in the barn under a cover for the entire off-season. Share some of these best practices with your customers to help them avoid unnecessary service and convince them of the importance of proper storage!

If the machine really did run when it was put away late last winter, there’s good reason to believe that it will run again easily enough. But the owner can make things a lot worse by cranking away on the starter or pulling the starter rope over and over. Most of the difficulties we see coming from storage and lack of use can be traced to two problems: gummed-up fuel and rodents.

Deep in New England, where snowmobiles live covered up and cozy for the summer in an unused corner of a hay barn, savvy owners don’t think twice about opening up the airbox and at least checking it before even pulling the rope or hitting the start button. Far from being turned away by gasoline fumes and oil smell, small rodents universally recognize a snowmobile or ATV airbox as a prime nesting location. Soft grass, pink insulation and anything fibrous and easily shredded is gathered by the local mouse population and tucked in alongside your air filter to make a cozy nest. Chipmunks nest in burrows underground, but if they get to an airbox first, they’ll happily fill it with seeds and nuts.

Needless to say, this unwanted material doesn’t do an air intake much good at all. And, depending on the design of the airbox, the main “storage” area for Mr. Chipmunk may be below the air filter and right up against the air intake for a carb or fuel injection system. It won’t take much imagination to guess what will happen to all that trash when the engine puts a little suction on it. So the first fall maintenance tool, for the hunting camp ATV or the snowmobile, is a Shop Vac. Careful inspection and cleaning of the air intake system avoids a lot of headaches when it starts getting a little too cold in the garage for serious wrenching.

The second starting problem is caused by gasoline that sits and slowly evaporates over the hot summer months. Depending on what was left in the float bowl of the carburetor before the sled was put away — Av-gas, street-corner E-10 fuel, maybe a few drops of water mixed in — sitting over the summer can turn it into a nasty sludge that clogs carb jets and makes starting all but impossible.

Also, ethanol-laced fuel, which is hard to avoid these days, can have mysterious effects on certain plastic pieces and types of flexible fuel line. Hoses and gaskets can become brittle, spontaneous leaks can pop up, and officially attributing any of this damage to our fuel supply is nearly impossible.

The best defense for any fuel related problems is to drain the fuel out and leave parts clean and dry when a machine is being stored for a period of time—especially on a conventionally carbureted machine.

Fuel-injected systems live under fuel pump-induced pressure that can prevent evaporation problems for many months, even all summer. And, the newest systems are carefully built with materials that are resistant to ethanol degradation, so fuel-injected machines suffer far fewer problems in storage.

If draining the carbs or fuel injection system is too laborious to even consider, fuel additives can have a positive mitigating effect against the “summer sludge syndrome.” Sta-Bil fuel stabilizer is a well-known favorite that really will alleviate a lot of gasoline storage problems.  We’ve had good luck with a newer ethanol-specific fuel additive called Star-Tron. Star-Tron merchandising claims the solution will cure all manner of evil properties of ethanol-laced fuel, and they may be right. All we know is a snowmobile properly treated with Star-Tron can emerge from the barn in late fall and be started with one healthy pull.

When a fuel system lies untreated and degrades to the point that starting and running the machine is impossible, there’s no alternative to removing the carbs and cleaning them. Sludge, gum and a pinch of dirt are usually found in the float bowls, and it’ll be necessary to remove all the carburetor jets, clean them with a carb spray and then blow them out with compressed air. It’s a nasty job. Many big shops invest in an ultrasonic cleaning machine and charge a fee to submerge carbs and restore them to a like-new condition. If you haven’t made this investment, it may be worth it!