I have got about ten flights on my ultimate with the os 1.60 and I still can not get this thing tuned in. The os 1.6o came out of my lanier edge 1.20 and it ran beutifully. When I switched the engine to the ultimate, I put on a cline regulator because I moved the tank over the cg. I have a good idle and a good top end swinging an apc 18x6w prop. I tried a zinger 18x6 which was not enough prop, and a 18x6-10 prop. the apc prop is giving me the best rpm at 8100 but with all three props the engine just doesn't have a very good mid-range. As a matter of fact it stinks on all three props. I started out using 5% nitro and I am now using 10%. I have a brand new #8 plug, and all this is at an elevation of 4500 ft above sea level.
What do i need to do? I am in the process of using larger diameter fuel line, but does anyone have any other suggestions?
Thanks in advance for your help.