Smokey Engine - Air/Fuel problem or Oil/Fuel problem?

[l008com]

I've got a 1989 Mercury 90hp and these past few years, it's running a lot smokier than it ever used to.
Looking in to it a bit, smoke can happen from a bad air fuel mix on a 2-cycle engine.
It can also happen from a bad oil-fuel mix going in to a 2-cycle. My motor is oil injected, so it's doing the oil mixing itself. Is there a way to determine which issue I may be having? I'm afraid to mess with the oil mix blindly because if I run it to lean and kill the engine, my days as a boater will be over

 

[Chris1956]

Check the fuel pump diaphram for damage. A damaged diaphram allows raw fuel into the crankcase. This can cause lots of smoke.