I'm still pretty new at all this so just want to get some feedback:

I'm running an OS 120AX with a Perry Pump and fuel tank at the CG. I installed a 'T' near the carb and a return line for excess fuel as per Connely/Perry instructions. I just switched to a fuel with full synthetic lubricant (what was available from a trusted brand), and installed a new OS A5 (cold) plug as per the OS manual. I set my needles as I always do, low end based on a perfect transition and high end a slight pitch richer than max rpm and flew. It was a bit windy and there was not much of a smoke trail. I landed my plane and noticed the exhaust was a mix of orangy brown and smoky grey. I tried making everything more rich (to the point of a dead stick on a touch-and-go) but could not get a heavy smoke trail. The good things I noticed were a very wet exhaust stream on the ground, and lots of oily goo on the bottom of my plane. I ran my plane at WOT on the ground and had another guy hold it nose up with no change in RPM.

Let me back up a little here: I ran this same setup the other day with a different brand fuel, with a small mix of castor in the lubricant. I did the same routine and noticed some castor varnish on the engine, and opening up the engine found dark brown varnish on the piston and in the exhaust. I found I had an OS8 plug in the engine which I think is too hot for the 120AX. I also found that this fuel has much less power and transition performance from the newer (Wildcat, 10% nitro, 18% full synthetic) fuel. It also had the same lack of smoke. I took this as a sign of running the engine lean.

I just want to be sure I'm not leaning out in the air. The fuel is a different color (and smell!) then I'm used to, and I'm not sure why I couldn't get more smoke from the engine. Like I said I am pretty new and feel like there are a lot of variables here, and no one in my club has experience with a Perry pump, nor is there really anyone I fully trust with tuning an engine. Right now I am nervous about performing vertical maneuvers without seeing the excess smoke trail.

My intuition is telling me that the synthetic oil might leave less of a smoke trail, the greyish color in the exhaust is probably OK and normal, just different from my 46AX with castor oil, and that the pump seems to be working well on the ground so I should trust that it is working well in the air.

Well thanks for reading and for your thoughts.