Fx Impact 2 .25 cal shooting NSA 34.9, 85 yard at 2 moa

Hello Air Gunners
I had a chance to get out last week to sight in and plink around. I set the PSI to 125, 4th line on valve adjuster and power wheel to max with an average of 943 fps. I sighted in at 45 yards, 5 shots touching each other. i moved to 85 yds, the groups open up to 1.5- 2 moa. I didn't have time to make any other adjustments. I'm thinking I have to adjust the valve adjuster to tighten the group or raise the psi more because it's not having enough velocity at that distance. What is my next step for keeping it under 1 moa?
thanks you