Happy to report I fix my rough engine running problem with the help from you guys!!
First off the correct NGK plugs were in the engine BUT the last owner didn't set the gap. It's suppose to be .030 and was just over .040
I cleaned the DFI module connection(black box with a buch of wires go into on right side of engine) and my Scag dealer gave me some insulating grease to apply.
Started up and purrrred like a new Scag.