How to Get Old Lawn Mowers Started

There are only two reasons why an old lawn mower won't start: no fuel or no fire. The fuel is the gasoline and the fire is the electricity that makes a spark off the plug. Each of these two components must work together to allow an old lawn mower to start, and if one or the other does not supply its part of the equation, the chances are that in an older lawn mower, it's not worth tinkering with anymore and it may be time to buy a new one.

Things You'll Need

• Spark Plug Wrench
• Spark Plug-New
• Gasoline-Fresh
• Starting Fluid Spray

Instructions

1. Add fresh gasoline to the tank. If the gas is more than three months old, it is not fresh. Drain the old gas into a bowl or other container, and pour in fresh gasoline. Take the old stuff to any gas station or hardware store to get it recycled.

2. Buy a new spark plug. Spark plugs are so inexpensive that it doesn't make sense to try and start an old lawn mower with the one that's already installed.

3. Unscrew the old spark plug with the spark plug wrench.

4. Spray a 1/2 second shot of starting fluid into the spark plug hole.

5. Install the new spark plug.

6. Set the mower throttle cable lever to choke.

7. Pull the starter rope and on the very first pull, the mower should fire. If it does not so much as fire or cough, pull the starter once more. Again, if it does not so much as fire, you have an electrical problem. It could be something easy like a broken spark plug wire, or something difficult like a burned out coil. Either one is now going to cost you time and money to repair, and you'll have to decide if it is worth it or not.

8. Pull the starter again if it originally fired. If it is not an electrical problem, the mower will run on the second or third pull. If it suddenly dies again, unscrew the spark plug and give it another shot of starting fluid.

9. Pull the starter, and if it runs but dies yet again, you have a carburetor problem and no gas is getting into the engine. This usually means that the jets and needle valves are gunked up and the carburetor needs to be rebuilt. You'll have to decide here whether it's worth the time and effort to get this done.

Tips & Warnings

• If you are unsure of using starting fluid, you can prime the cylinder by pouring in a capful of gasoline and then screwing in the spark plug. However, gasoline is not as volatile as starting fluid, so you may have to pull the starter cord several more times before the motor fires and/or runs.

• Never use starting fluid in newer lawn mowers. Because of it's volatility, there is a chance that it can ruin the drive train inside of the motor, and although that is a slight possibility, a newer motor would be better off primed with gasoline to start or taken into a shop and have it looked at.