I have a customer that has a zero turn mower with a 25hp kohler command eng. It has a miss fire on one side only, not a dead miss but a very weak cyl. He has check compression it is 155 on both cly, did cly leak down good on both side, replaced ign coil on weak side , checked valve lift on both side, checked flywheel keyway, cleaned carb. everything looks good and is within specs, but still has a very weak cly. any ides or thoughts would help THANK YOU