spark plug replacement

[anut]

How often do you replace spark plugs? every season, every 100 hrs? I have 1998 merc 150HP offshores (2-cycle) and am taking on the maintenance.
thanks

[Nauti Buoy]

Every 100 hours seems to be a popular benchmarck. As for me, I'll replace the plugs after Spring Prep and hang on to a few of the older plugs as spares after I've cleaned them up and regaped them. I'll keep these spares in the boat in case something goes sour. Prior to this, I'll winterize the boat using the old plugs and again in the Spring when I burn off the fogging oil. Then I'll install the new plugs.

[Go Fish]

If I'm lucky enough I change plugs twice a season.

Once in the spring after the fogging oil and last years gas has been run out of the motor and tank.

And then again after I break the 100 hour mark...I haven't made it to the 200 hour mark in one season yet --124-3

Every fifty hours I do a decarbon treatment on the motor and afterward, pull the plugs for regapping and a coat of dielectric grease on the plug wire terminal and tightning nut