How often to change plugs

[bambino]

I have a 2006 Yamaha 250 4 stroke. When I had 2 stroke motors, I always changed plugs in spring after the winter layover, but is it necessary with 4 strokes? I don't fog this motor by spraying through the intake while running, I spray fogging fluid into the spark plug holes and crank the motor for a few seconds without it starting. Since I last changed these plugs I've put 110 hour on.

 

[robert graham]

Re: How often to change plugs

On a 4 stroke I doubt the plugs need changing very often at all, especially if the motor is well-tuned and running correctly(pretty darn lean). On my 2 stroke 90HP I personally never change the plugs, but I do sand blast the carbon off of them from time to time, same plugs since 1999. I think a lot of folks just "change the plugs", like their daddy and grandfathers used to do, but not all that much required anymore, with the modern motors and spark plugs. That little Harbor Freight Spark Plug Sandblaster($15) has paid for itself many times on all my motors. Good Luck!