mcomeaux53,
One of the list advertisers, LEAF (a Rotax dealer), Located in Wisconsin has two sizes of the heat conductive paste.... they sell .14 gram packets or a larger tube (the larger tube costs a lot and more and is more than a person needs unless they are a shop). I recently bought two of the .14 gram tubes...one tube is more than enough for doing the threads of a set of spark plugs.
Any Rotax service center should have it. CPS in California for example.
Sincerely,
Dave S
KF7 Trigear
912ULS Warp Drive
St Paul, mn