Margay has specific 4 cycle chassis:
Margay Brava 4.15 (more tuning options)
Margay Ignite (very reasonable entry level)
Have you checked the float level? Since you mentioned it being a new engine, Briggs recommends checking and setting the Float level as they tend to move during shipment at times.
Hope this helps,
Tony
Briggs LO206 for myself and my son
Out of curiosity What “Program” is this in comparison to what Briggs has already established?
Thanks,