I think this has been happening for a while now when ever I go past 7 grand puffs of smoke comes out. If I'm in my drive way and slowly bring the car to WOT then mounds and mounds of Blue smoke spuw out the back. i have been using a premix, premium synthetic envinrude outboard 2 cycle. I don't see a loss in performace but at about 5 grand my car turns to a high pitch weed eater noise. I belive I'm just cleaning the carbon out of my 154k 13b but if this is a sign of going bad let me know

 

I wouldnt' worry too much about the sound; at about 5k the aux. ports kick in and the tone changes (assuming you have an 86-91 N/A). As for the smoke, I run premix in my '90 GXL and it turns the bumper yellow just from the 2-cycle oil. A little puff of smoke at taxing engine speeds is probably not a bad thing in my opinion.

 

Sounds normal for your car...I wouldn't worry too much especially if you don't notice a loss in performance.