I have a Cub Cadet with a 54" deck and a 27hp Kohler Courage engine. This is my 5th year with the mower and it has approx. 530 hours. After 1st 50 hours I changed oil to a full synthetic 10W30 and have using 10W30 exclusively until this year. I change oil at the beginning of season and mid way through season (2x/yr) and average around 120 hours annually. The 27hp Kohler has always been noisy with a lot of lifter clicking that I find both loud and annoying. The Kohler does not consume any oil in between oil changes. This year, I changed oil to a full synthetic straight 30W and did not notice any change in idle speed, power or any reduction in noise from motor. 2 weeks ago, I did my mid season oil change and decided to try a full synthetic 15W50 from Mobil 1. Within 15 minutes the motor become very quiet and I did not notice any change in idle speed. I started mowing and also did not notice any loss of power at all. From a noise level (clicking, knocking, etc.) the change has been remarkable. It's like I have a new motor in my Cub Cadet. I only use mower to mow grass so it is garaged in the winter. I don't know if 15W50 is a good idea for a new Kohler motor, but it is awesome for one that has been well maintained with over 500 hours. Anyone else use 15W50?
Kev
