Oily plugs

[Fish Hound]

I have a small boat I bought from my father in laws estate and has a 1997 25 hp mercury on it. It is idling a little rough and  did not know when last time plugs were changed. When I got them out they were fairly oily, not dripping but wet. I know the fuel mix is right so if these are oily is that a sign of bad rings or something else? Should I go with a hotter plug? Spec sheet says NGK BPZ8H-N-10 and that was what was in it. Other than the oil they "looked" good and gap was correct at .040. If plugs are not the issue then maybe just needs idle adjustment? Thanks 

[fishinwrench]

Carb float setting needs to be checked, as does the throttle pickup timing, and idle mixture setting.

A pin hole in the fuel pump diaphragm will dribble raw fuel into the crankcase, so if everything I mentioned first checks good then that's the only other way it can be getting a too rich mixture.  

[Fish Hound]

Thanks for feedback Wrench. Will check these out and see if I can get it smoothed out. Would trolling for long period of time cause the oily issue? My 82 year old dad rode his bike down here to Springdale for BB&BBQ and wanted to go fishing. He likes to troll so we put in at Blue Springs on Beaver went up to War Eagle Marina and back so a long period. I did run it on plane at the very end but that was only for 4-5 minutes.

Thanks

[fishinwrench]

1 hour ago, Fish Hound said:

Would trolling for long period of time cause the oily issue?

Not if the the things I mentioned above are set properly, and the engine doesn't have any other issues.   People have been trolling with 25 Merc 2-strokes for 70 years!