I have an OS .46 LA. I am having trouble with setting a low idle in the plane. I have the engine mounted at a 90. the engine runs good and revs out but once it returns to idle it dies. the only way to keep it running is keeping it at 28-3000 rpm anything under it dies. I pulled the engine from the plane and resealed everything and bolted it to the bench, it run fine and would keep a stable idle at 18-2000 RPM but once back in the plane the problem returns. I already replaced the fuel lines to the tank and inside it, just to rule that out. what else can it be? at that idle the plane creeps away.