All carb specs check out 100% good. Thanks for the advise, and yes I have a system. I have been jetting stand up jet carbs on race engine setups for many years, and have extensive knowledge of street rod jetting, but this is strange. I have never had a two stroke jetski carb exhibit this. The closest would be fouling from starting a engine many times over the winter, and never putting the craft in the water.
That said, the plugs appearance indicates a severely rich mixture, and if I do not "raise caine" so to speak and keep the revs up, when I do open it up on a long stretch, you can tell the engine/sparkplug is cleaning itself out from being too rich....but it is not bothersome really...plenty of power at hand! All this tells me to drop jet size very gradually and gauge results.
I have alway jetted two stroke on the rich side, better safe than siezed. So this motor being "rich" is not a issue, but constant plug fouling would be. The jetting benchmarks must be explored.
On the oil issue, are the Motul and Shell products full synthetic or a blend? Is is safe to run a 40:1 ratio on these highly tuned/ reving motors?, keeping in mind the book calls for 32:1? I believe in going richer than a manufactures' recommendation, but not leaner? (with proper jetting adjustments)
Well, like I stated earlier I have the clip on groove 1, 48 pilot and the stock 178. We will see what happens tomorrow.
Could the engine just be set up too cold? too much water flow, too much heat given up in the radiator? I tend to think not, as I have run my ski engine pretty darn cool with no plug problems.
Maybe we should Yamaha involved in this???