Another thing... I changed both plugs when replacing coils. Then when I did compression test I noticed 1 plug slightly fouled while the other brand new.
I have a Kubota with a kohler CH20 twin cyl. horizontal with 1300 hrs. It's been a great mower. Started bogging down under a load and had a pretty bad oil leak. Had to remove the motor to change coils and crankshaft main seal. Cleaned up and found another oil leak at oil cooler. Back together...