Welcome Dave.
Sorry I cant help you with oil selection.
I know of at least one other using mobile 1

Steve Izett
Perth Western Australia
> On 30 Dec 2017, at 12:07 pm, Pam & Dave Williams padajute@idcnet.com <flyrotary@lancaironline.net> wrote:
>
> Hello,
>  
> I am new to the group. I have a Tailwind with a 13B with Tracy’s Ignition, Injection, and Redrive. I am considering using an oil from AeroShell called Sport Plus 4. It is synthetic oil with an additive for gear boxes. It is used in Rotax engines with a gear drive with a common sump same as my 13B \redrive. It also is compatible with 100LL fuel which I use. Any comments and experience would be helpful.
>  
> Thanks,
>  
> Dave Williams
> padajute@idcnet.com