Hi Naftali, I was just about to ask that question of others this morning.

I've been running Coolpower blue at 10% which I believe is their standard viscosity.

I did run it at 20% for a couple of months when I first bought the engine, but I couldn't seem to get it running right all the time although the rest of the world had no problems running 20% oil. It was my first YS engine and I was on a steep learning curve (seems I still am) but it was easier (more idiot proof?) to tune on 10% oil.

While I was in the LHS, he pointed to a bottle of the Coolpower purple multi-viscosity oil and I was going to ask about that this morning.

I need a new bottle of oil and was wondering if the switch would be worth it and what percentage I should run?