What do I have to do to winterize my pressure washer?

Gasoline goes bad after sitting for an extended period of time.
Old school people would drain the gas out of the tank but found this lead to rust forming in the tank.
Now it is best to fill the tank with high octane gas and use a winterizing fuel additive to prevent problems.
Also remove any water from the hoses.
In the spring replace the gas and change the oil and you should be good, changing the spark plug would also be beneficial.

hello, there is a winterize bottle you can buy at most home or hardware centers. hope this helps.