I could mean there is too much water in your exhaust system. After you've ran your ski a good while take out your water box and see if it loaded down with a bunch of water. A little is fine but a bunch of nasty water could mean you have other problems. Also if that white smoke disappears almost instantly after it leaves the exhaust you know that it is water. If it hangs around and is kind of blue-ish in color you are running rich which is usually okay in older skis. Plugs are tell tale signs of your mixture. Do a "plug chop" test. Details of it are on group k's website under carb tuning.