Lawnmowers use four-cycle engines. They differ in this way from smaller yard machines like a chainsaw for example, which uses only a two-cycle engine. For machines like lawnmowers, gas and oil must be added to two separate tanks. Don’t panic however, if oil gets into the gas tank, the lawnmower won’t explode. However the gas tank might get damaged. If you do add oil into the gas tank, there are ways to fix this problem.
One way to get rid of the oil is to drain the gas tank by tilting the lawnmower. Drain as much oil out as possible. Once the gas tank is drained completely, you can use the lawnmower as you normally would. The engine will smoke for a while, as oil that is leftover will burn off through the exhaust. This is the simplest method to getting rid of the oil, but not the most effective way.
The second method of removing oil from the gas tank is to actually take out the tank and pour the oil out. Remove the tank and pour out the oil into either a container or an oil absorbing pad. Then, in order to completely rid the tank of oil, get some dishwashing liquid and combine it with some warm water to be used to clean the remainder of the gas tank. Dishwashing liquid is effective because it cuts grease. When the tank is fully cleaned, dry it using compressed air in a can. Once the tank is dried (completely, as water will also damage the gas tank), you can now replace it and fill it with gas.
What if you accidentally add oil to the gas and then try to start it? This is also fixable. In this situation, the oil is probably in the fuel line. In this case, you will need to remove the fuel line and replace it. Once you do this, try starting the lawnmower. If it does not start, try spraying starter fluid into your lawnmower’s engine carburetor. This should cause it to start normally.
Every problem has a solution. It’s also a good idea to regularly clean out the gas tank even if you did not get oil in it, as this will ensure it continues to function.