Over the years, I have learned about mothballing small engines the hard way. Years ago I failed to mothball engines correctly, just shutting them down and forgetting about them. Several years later I attempted to start them and ended up taking them to the repair shop. It was not a cheap experience.
Since then if I am going to let an engine sit for any length of time I am careful to mothball it. My limit is about 90 days, anything over that and I mothball. Since I have been doing that, I have not had any further problems.
I mothball two and four stroke engines slightly differently. First with both types, I clean the engine prior to getting it ready for storage. I make sure there is no debris on the exterior that is going to collect moisture or cause corrosion.
Mothball Small Engines, 2 stroke (requires oil & gas mix)
- Start up the unit and run the engine until it stops from running out of gas. If the gas tank is full, you may want to drain most of the gas out prior to running it out of fuel. After the engine stops, pull the starter cord a couple of times until the engine no longer sputters from gas remnants left in the fuel system.
- The next step is to remove the spark plug, squirt a small amount of lubricant (I use Marvel Mystery Oil) into the spark plug hole, and pull the starter cord a few times. This will lubricate the engine’s cylinder parts. Reinstall the spark plug. Your equipment is now ready for storage.
- Store it in an area in which it stays clean and dry. Exposure to moisture can cause damage.
- When you take it out of storage, fill it with the correct fuel mixture and it should start right away.
Mothballing Small Engines 4 Stroke (requires straight gasoline only – NO oil mix)
- Start the engine and let it run until it stops from lack of fuel
- Remove any remaining fuel from the carburetor. This is done several ways depending on the manufacturer of your equipment. First you must find your carburetor’s fuel bowl by following the fuel line from your fuel tank to the engine.
- If your fuel bowl has a drain on the bottom, loosen the drain bolt or valve and drain out the remaining fuel.
- If the fuel bowl has a big bolt in the middle, break the bolt loose and drain the fuel. Then retighten the bolt.
- If your fuel bowl does not have a drain or bolt in the middle of it, you will have to remove the fuel bowl. This can be done by removing the two screws at either corners of the fuel bowl where it bolts to the carburetor. Remove the bowl and dump out any remaining fuel. Then replace the bowl onto the carburetor.
- Remove the spark plug and squirt a small amount of lubricant into each cylinder. Pull the starter cord a few times to lubricate the cylinders. Replace the spark plugs.
- Place in a clean dry area to protect it from moisture.
It takes a bit of work to mothball small engines in this manner, but you can count on them starting when you really need them.