I must interject the prop that has resolved a LOT of the run issues Pat and I had with the LA 46, ( ok so they werent all that dramatic of issues,, ) The APC 12.25 x 3.75 prop is a really solid performer on this engine. No reduced diameter, no changing nothing, just bolt it on, use 10-22 powermaster, .272 -.275 venturi, supertiger sized needle assembly, thunderbolt plug, ( i dont use the idle bar plug) 9800rpm