Hello,
I have an OS FL70 4 stroke engine, and I have a concern about it:
Recently I have been tuning it to get it running nicely. My fuel is S&W 15% 4 cycle with castor/synthetic blend. The propeller is a 12X7. After a lot of adjusting, the engine seems to be running well. But I'm a bit worried. My engine, when idling (at 2,100 RPM) makes a lot of visible smoke. When I raise the throttle, the smoke practically disappears! Here is a video of the problem:
[youtube]http://www.youtube.com/watch?v=Ofiy2Tl7J3I[/youtube]
This confuses me though. I set the engine normally. I was able to get the max RPM by adjusting the high speed needle and got to 9,400 RPM. I then richened the high speed needle so it ran at 9,200 RPM, which is about 3 clicks richer. Then, I set the low speed (air bleed screw) to the smoothest transition, and I was happy with about a 1 second transition. According to my process, the engine should be running slightlyrich,notlean!
Do you think I am running the engine too lean on the high speed?
I shouldn't be; considdering that richening it any more makes me lose a ton of performance and it makes the engine run inconsistently.

What do you all think?

Thanks
Mike