S7 engine mount

I have a Kitfox S-7 from Skystar with a 912uls and 650 hours on it.

I bought two engine mounts P/N 90048.000, last spring and used them to replace the two lower mounts. I thought they were drooping too much.

The s7 I have was built from the skystar manual and I used it to replace the mounts.

It calls for a 1 7/16" rubber bushing P/N 01146.000, which was missing before I replaced the mounts. (My building partner did it).

I installed the bushing and new mounts and noticed a small buzzing vibration after that.

I have since rebuilt the carbs, and the gearbox and have gone full circle with the vibration. Yes I balanced.

Is there a new mount or method in the newer S7's?